text stringlengths 454 608k | url stringlengths 17 896 | dump stringclasses 91 values | source stringclasses 1 value | word_count int64 101 114k | flesch_reading_ease float64 50 104 |
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In this assessment you'll use the Django knowledge you've picked up in the Django Web Framework (Python) module to create a very basic blog.
Project brief
The pages that need to be displayed, their URLs, and other requirements, are listed below:
In addition you should write some basic tests to verify:
- All model fields have the correct label and length.
- All models have the expected object name (e.g.
__str__()returns the expected value).
- Models have the expected URL for individual Blog and Comment records (e.g.
get_absolute_url()returns the expected URL).
- The BlogListView (all-blog page) is accessible at the expected location (e.g. /blog/blogs)
- The BlogListView (all-blog page) is accessible at the expected named url (e.g. 'blogs')
- The BlogListView (all-blog page) uses the expected template (e.g. the default)
- The BlogListView paginates records by 5 (at least on the first page)
Note: There are of course many other tests you can run. Use your discretion, but we'll expect you to do at least the tests above.
The following section shows screenshots of a site that implements the requirements above.
Screenshots
The following screenshots provide an example of what the finished program should output.
List of all blog posts
This displays the list of all blog posts (accessible from the "All blogs" link in the sidebar). Things to note:
- The sidebar also lists the logged in user.
- Individual blog posts and bloggers are accessible as links in the page.
- Pagination is enabled (in groups of 5)
- Ordering is newest to oldest.
List of all bloggers
This provides links to all bloggers, as linked from the "All bloggers" link in the sidebar. In this case we can see from the sidebar that no user is logged in.
Blog detail page
This shows the detail page for a particular blog.
Note that the comments have a date and time, and are ordered from oldest to newest (opposite of blog ordering). At the end we have a link for accessing the form to add a new comment. If a user is not logged in we'd instead see a suggestion to log in.
Add comment form
This is the form to add comments. Note that we're logged in. When this succeeds we should be taken back to the associated blog post page.
Author bio
This displays bio information for a blogger along with their blog posts list.
Steps to complete
The following sections describe what you need to do.
- Create a skeleton project and web application for the site (as described in Django Tutorial Part 2: Creating a skeleton website). You might use 'diyblog' for the project name and 'blog' for the application name.
- Create models for the Blog posts, Comments, and any other objects needed. When thinking about your design, remember:
- Each comment will have only one blog, but a blog may have many comments.
- Blog posts and comments must be sorted by post date.
- Not every user will necessarily be a blog author though any user may be a commenter.
- Blog authors must also include bio information.
- Run migrations for your new models and create a superuser.
- Use the admin site to create some example blog posts and blog comments.
- Create views, templates, and URL configurations for blog post and blogger list pages.
- Create views, templates, and URL configurations for blog post and blogger detail pages.
- Create a page with a form for adding new comments (remember to make this only available to logged in users!)
Hints and tips
This project is very similar to the LocalLibrary tutorial. You will be able to set up the skeleton, user login/logout behaviour, support for static files, views, URLs, forms, base templates and admin site configuration using almost all the same approaches.
Some general hints:
- The index page can be implemented as a basic function view and template (just like for the locallibrary).
- The list view for blog posts and bloggers, and the detail view for blog posts can be created using the generic list and detail views.
- The list of blog posts for a particular author can be created by using a generic blog list view and filtering for blog objects that match the specified author.
- You will have to implement
get_queryset(self)to do the filtering (much like in our library class
LoanedBooksAllListView) and get the author information from the URL.
- You will also need to pass the name of the author to the page in the context. To do this in a class-based view you need to implement
get_context_data()(discussed below).
- The add comment form can be created using a function-based view (and associated model and form) or using a generic
CreateView. If you use a
CreateView(recommended) then:
- You will also need to pass the name of the blog post to the comment page in the context (implement
get_context_data()as discussed below).
- The form should only display the comment "description" for user entry (date and associated blog post should not be editable). Since they won't be in the form itself, your code will need to set the comment's author in the
form_valid()function so it can be saved into the model (as described here — Django docs). In that same function we set the associated blog. A possible implementation is shown below (
pkis a blog id passed in from the URL/URL configuration).
def form_valid(self, form): """ Add author and associated blog to form data before setting it as valid (so it is saved to model) """ #Add logged-in user as author of comment form.instance.author = self.request.user #Associate comment with blog based on passed id form.instance.blog=get_object_or_404(Blog, pk = self.kwargs['pk']) # Call super-class form validation behaviour return super(BlogCommentCreate, self).form_valid(form)
- You will need to provide a success URL to redirect to after the form validates; this should be the original blog. To do this you will need to override
get_success_url()and "reverse" the URL for the original blog. You can get the required blog ID using the
self.kwargsattribute, as shown in the
form_valid()method above.
We briefly talked about passing a context to the template in a class-based view in the Django Tutorial Part 6: Generic list and detail views topic. To do this you need to override
get_context_data() (first getting the existing context, updating it with whatever additional variables you want to pass to the template, and then returning the updated context). For example, the code fragment below shows how you can add a blogger object to the context based on their
BlogAuthor id.
class SomeView(generic.ListView): ... def get_context_data(self, **kwargs): # Call the base implementation first to get a context context = super(SomeView, self).get_context_data(**kwargs) # Get the blogger object from the "pk" URL parameter and add it to the context context['blogger'] = get_object_or_404(BlogAuthor, pk = self.kwargs['pk']) return context
Assessment
The assessment for this task is available on Github here. This assessment is primarily based on how well your application meets the requirements we listed above, though there are some parts of the assessment that check your code uses appropriate models, and that you have written at least some test code. When you're done, you can check out our the finished example which reflects a "full marks" project.
Once you've completed this module you've also finished all the MDN content for learning basic Django server-side website programming! We hope you enjoyed this module and feel you have a good grasp of the basics! | https://developer.mozilla.org/tr/docs/Learn/Server-side/Django/django_assessment_blog | CC-MAIN-2020-45 | refinedweb | 1,255 | 63.09 |
event hiding in inherited class not working
I'm trying to hide an event from an inherited class, but not via EditorBrowserable attribute. I have a DelayedFileSystemWatcher which inherits from FileSystemWatcher and I need to hide the Changed, Created, Deleted and Renamed events and make them private. I tried this, but it does not work:
/// <summary> /// Do not use /// </summary> private new event FileSystemEventHandler Changed;
The XML comment is not showing in IntelliSense (the original info is shown). However, if I change the access modifier to public, the XML comment is shown in IntelliSense.
Any help is is welcome.
You don't want to use it but it trivially solves your problem:
class MyWatcher : FileSystemWatcher { [Browsable(false), EditorBrowsable(EditorBrowsableState.Never)] private new event FileSystemEventHandler Changed; // etc.. }
The only other thing you can do is encapsulate it. Which is doable, the class just doesn't have that many members and you are eliminating several of them:
class MyWatcher : Component { private FileSystemWatcher watcher = new FileSystemWatcher(); public MyWatcher() { watcher.EnableRaisingEvents = true; watcher.Changed += new FileSystemEventHandler(watcher_Changed); // etc.. } public string Path { get { return watcher.Path; } set { watcher.Path = value; } } // etc.. }
Programming and Problem Solving with Visual Basic .NET, Overriding If you look at the definition of the Text property in the TextBox class in the table tells us every property, method, and event that is available in the class. Hiding When a derived class defines a property with the same name as One If you are not explicitly specify "override" but use the same name, you simply hide the inherited member behind a completely different member and get the warning for that; you can suppress this warning with new. But you cannot override an event, so all you do is hiding. I don't see a reason for doing it in your case.
If you inherit it, you have to provide it.
Maybe instead of inheriting:
Public Class DelayedFileSystemWatcher : Component { private FileSystemWatcher myFSW; public DelayedFileSystemWatcher { myFSW = new FileSystemWatcher(); } }
The Common Language Infrastructure Annotated Standard, 8.10.3 Property and Event Inheritance Properties and events are 8.10.4 Hiding, Overriding, and Layout There are two separate issues involved in base type (hiding) and the sharing of layout slots in the derived class (overriding). Hiding is I'd say the following rule could make sense for displaying the event in the "Event" Section: "If two defined events have the same identifier, do not duplicate the entries in the events section, but include docs (with pointers to the inherited event definition) for the actual module / class page".
You can't make something that's public in the base class into private in the derived class. If nothing else, it's possible to cast the derived class to the base class and use the public version.
The way you hide the base class's event actually works, but only from where the new event is visible, that is, from inside the derived class. From outside, the new event is not visible, so the base class's is accessed.
C# 5.0 Programmer's Reference, Notice how it uses the class instead of an instance to identify the event. (You can also avoid this problem if you don't use static events.) hiding. and. overriding. events. Events are a bit unusual because they are not inherited the same way The OverdraftAccount class can use the new keyword to hide the Overdrawn The class Mustang inherits the method identifyMyself from the class Horse, which overrides the abstract method of the same name in the interface Mammal. Note: Static methods in interfaces are never inherited. Modifiers. The access specifier for an overriding method can allow more, but not less, access than the overridden method.
Differences Among Method Overriding, Method Hiding (New , No unread comment. loading. The "override" modifier extends the base class method, and the "new" modifier hides it. The "virtual" keyword modifies a method, property, indexer, or event declared in the base class and allows it to be If a method is not overriding the derived method then it is hiding it. Note. Do not declare virtual events in a base class and override them in a derived class. The C# compiler does not handle these correctly and it is unpredictable whether a subscriber to the derived event will actually be subscribing to the base class event.
Hide base class property in derived class, This is my Base class public class BaseClass { public string property1 { get; set; } abstract or virtual implementation of an inherited method, property, indexer, or event. PawarName); // not hidden } public class Pawar { public virtual System. class House : Building // DerivedClass inheritance at work The basic steps for overriding any event defined in the.NET Framework are identical and are summarized in the following list. To override an inherited event Override the protected On EventName method. Call the On EventName method of the base class from the overridden On EventName method, so that registered delegates receive the event.
Inheritance, Jun 29 - Jul 2, ONLINE EVENT What's the meaning of, Warning: Derived::f(char) hides Base::f(double) ? For safety: to ensure that your class is not used as a base class (for example, to be sure that you can copy objects without fear of slicing). Although a virtual call seems to be a lot more work, the right way to judge Hiding Properties. When. | http://thetopsites.net/article/58458287.shtml | CC-MAIN-2020-40 | refinedweb | 887 | 61.46 |
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How should i get days of a month automatically(ie,In Jan it should come 31,Feb it should be 28...) in my report
I am using Openoffice+ base_report_designer module for printing this requirement.
But i dont know how to implement this.. Can any one help me ?
In python create function using current date to calculate End of the Current month.
The below link may be useful to Create function in python report file and call in Openoffice
report \attendance_errors.py
def __init__(self, cr, uid, name, context): super(attendance_print, self).__init__(cr, uid, name, context=context) self.localcontext.update({ 'time': time, 'lst': self._lst, 'total': self._lst_total, 'get_employees':self._get_employees, }) def _get_employees(self, emp_ids): emp_obj_list = self.pool.get('hr.employee').browse(self.cr, self.uid, emp_ids) return emp_obj_list
report \attendance_errors.sxw file open with openoffice
[[ repeatIn(get_employees(data['form']['emp_ids']),'employee') ]]
How can we connect this code to our reports.
eg: get_periods function is defined in the py file for getting the month and call this functin in report like this. [[get_periods(o.value)]] But Error message like this " name 'get_periods' is not defined " (I manually send the report to server.) Place the .rml and .py file in the report folder of hr_attendance module . Then upgrade the module.
Or Without using python code. How can we implement this.
report in .ODT format
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Hi All,
is any one implemented POST-Get-Redirect scenoria with WCF WebAPI . is so how to do it.
Do you mean where every POST is redirected to the same request, but as GET?
That doesn't apply to APIs... that only applies to Web UIs.
No , Once the post a resource back to the server you want to redirect the Client to the different page ,Its like giving 301,302 to the Client
Sounds like your answer is "yes", not "no".
I don't think that that methodology should be anywhere near WebApi.
:) ..
May be a small problem and solution approach will help you understand more..
Lets imagine i have a Customer representation from the server to the client and there is an edit happened in client and i will post the edited data to the server and ask the client to move to the different Resource . How will you do through REST..
You don't do that with REST.
With rest when you edit a resource, you return the edited resource in the response.
Anyways. You can do it like this:
public class myservice
{
public HttpResponseMessage<int> Post(int x)
{
var m = new HttpResponseMessage(HttpStatusCode.Redirect);
m.Headers.Location = new Uri("");
m.Content = new ObjectContent<int>(1);
return m;
}
}
You mean to say Put can't return 301 or 302 as the success code .Is there any reason in not doing it
I didn't say can't, I meant it shouldn't.
If a user asks for one resource, why are you giving them another one. That doesn't make any sense.
IMHO ,Hypermedia as engine of application state gives the client a direction to the which is the next logical to take after each action . According to me PUT Verb is a Action on the resource should also say can say which is the next action the client should
take.Correct me if i am wrong
Well this is why there are so many derivations of what "REST" means ;)
One person implements it one way, the other another. If you follow my example above, that should give you your intended result.
Are you sure you want to delete this post? You will not be able to recover it later.
Are you sure you want to delete this thread? You will not be able to recover it later. | https://wcf.codeplex.com/discussions/299083 | CC-MAIN-2017-09 | refinedweb | 397 | 73.68 |
Hi I'm just using Playfab; I want to declare. Why is not it coming to autocomplete? using Playfab; The red line is recognized as an error and can not be compiled. Help,.... If you delete and reinstall the sdk, the same phenomenon will be repeated.
In my other projects using PlayFab; This line works correctly (no git hub is used).
However, this project is being shared with many people through a bit-bucket.
Is this causing an error because reason above ??
Answer by Jay Zuo · Mar 25 at 07:15 AM
Without your project, it's hard to say why you have this issue. I'd suggest you remove both PlayFabEditorExtensions and PlayFabSdk folder first and then comment out all PlayFab related code and make sure there is no error in your project. Then you can reinstall PlayFabEditorExtensions and PlayFabSdk and add the code back on by one. Title ID is not related for this issue. Since your project is shared with others, it's possible you didn't commit all necessary files or someone else pushed wrong code. You may need to check your code by yourself.
Reinstallation does not work.
I can not even search for this problem. Is it a problem only for me? Only in this project, vscode has sdk turned into a yellow color.
using PlayFab; << I do not know why I can't use this sentence ....
I'm afraid this problem is only for your project. Have you tried to create a new project? I'd believe there should be no issue to use PlayFab in that new project.
Answers Answers and Comments
2 People are following this question. | https://community.playfab.com/questions/27962/help-me-namespace-define-error.html | CC-MAIN-2019-26 | refinedweb | 276 | 76.11 |
4.3 Configuring a Domain Controller
Installing Active Directory
Before installing the Active Directory on your Windows 2000 server, you must have a plan. Unlike using Windows NT 4.0, you need a lot more information than just knowing if the server you are installing will be a Primary Domain Controller or a Backup Domain Controller. With Windows 2000, you must know exactly how this Domain Controller fits into your enterprise. Principally, you need to know the following about this Domain Controller:
Will it be in a new Domain or a replica of an existing Domain?
Will it be in a new tree or in an existing tree within your enterprise?
Will it be in a new forest or an existing forest?
A New Domain Versus a Replica of an Existing Domain
In Windows NT 4.0, this would be the same as asking whether this server will be a Primary Domain Controller or a Backup Domain Controller. Choosing to create a replica of an existing Domain is the same as creating a BDC in a Windows NT 4.0 environment. However, because Windows 2000 allows multi-master updates of the accounts database, there are no Primary Domain Controllers and Backup Domain Controllers, just Domain Controllers. The term replica simply means that the Domain name context will be duplicated from another Domain Controller in the same Domain.
A New Tree Versus an Existing Tree Within Your Enterprise
A tree simply defines a hierarchical naming context. For each child in the tree, there exists exactly one parent. There are three rules that determine how trees function in Windows 2000:
A tree has a single unique name within the forest. This name specifies the tree's root. Be aware that tree names cannot overlap. If mycompany.com is a tree, Europe.mycompany.com cannot exist as a separate tree in the forest. It can exist only as a child Domain within mycompany.com.
The tree has a contiguous namespace. This means that children Domains are directly related to the Domains above and below themselves.
Children Domains inherit the naming from their parent. For example, if mycompany.com is a tree, europe.mycompany.com and asia.mycompany.com would be children within that tree.
A New Forest Versus an Existing Forest
A forest in Windows 2000 is the group of one or more Active Directory trees. All Domains in the forest share a common schema and configuration-naming context. However, it is important to note that separate trees in a forest do not form a contiguous namespace, even if peer trees are connected through two-way transitive trust relationships.
Table 4.3.1 provides a list of other critical information needed before installing the Active Directory on a Windows 2000 server.
Table 4.3.1 Information Needed Before Installing the Active Directory
After you have gathered all the necessary information, you are ready to install the Active Directory. There are three main ways to install the Active Directory on a Windows 2000 server:
The Active Directory Installation Wizard will be automatically launched upon upgrading a Windows NT 4.0 Domain Controller.
From Configure Your Server Wizard, select the Active Directory Tab. Follow the instructions to launch the Active Directory Installation Wizard.
From the Start menu, click Run and execute DCPROMO.EXE.
If you have gathered the necessary information prior to running the Active Directory Wizard, you should be able to follow the prompts provided. Upon completion, the Active Directory will be installed on your server.
Can I Move the Domain?
If you decide that you need to move this Domain to another location within your forest, Microsoft has provided a tool.
For more information, see "Going Deeper: Restructuring Domains" later in this chapter.
Configuring Active Directory Replication
The).
There are two types of Active Directory replication in Windows 2000. Each one has its own set of rules and behaves very differently from the other. In order to configure Active Directory Replication, you need to understand the following:
Replication within a site
Replication between sites
How to use the Active Directory Sites and Services MMC snap-in
Replication Within a Site
Replication within a site is optimized to reduce the time it takes changes to reach other Domain Controllers. To do this, the Knowledge Consistency Checker (KCC) creates a bi-directional ring of connections between all other Domain Controllers in that site. However, as the number of DCs in a site grows, the replication latency continues to be increased. To solve this problem, Microsoft implemented an algorithm, ensuring that all updates are fewer than three hops from the source of the change to the destination. During the initial creation of this replication topology, it is possible for duplicate or unnecessary replication paths to exist. However, the KCC is smart enough to detect these redundant connections and remove them. Finally, it is important to note that replication within a site cannot be configured nor have a schedule applied to it.
Replication Between Sites
Replication between sites is configured to optimize the amount of data sent over the network, given your implementation's tolerance for latency. Each group of sites is connected with a site link. Each of these site links has a relative cost (that you assign). The KCC then generates a least-cost spanning tree, as calculated by the relative cost of the site links. To further optimize the data sent, replication between sites is compressed. Although this causes slightly higher utilization on the target and destination servers, it allows you to more efficiently use your physical connections. Inter-site replication can also be configured to store changes and replicate from a minimum of every 15 minutes to a maximum of every 10,080 minutes. Finally, this type of replication has a configurable schedule of one-hour blocks. For example, you can configure replication to only occur between 5:00 p.m. and 8:00 a.m., if necessary.
For more information on the algorithms used by Active Directory Replication, see the Microsoft White Paper, "Active Directory Architecture."
Using Active Directory Sites and Services
Active Directory Sites and Services is the MMC snap-in that allows you to configure Active Directory replication. Specifically, you can do the following:
Create sites
Create subnets
Create IP site links
See Figure 4.3.1 for an example of using the Active Directory Sites and Services MMC snap-in.
Figure 4.3.1 Configuring sites, subnets, and site links using the MMC snap-in.
You can launch the Active Directory Sites and Services MMC snap-in from the Administrative Tools program group on the Start menu.
For more information on configuring and installing Administrative tools, see Chapter 3.3, "Using Administrative Tools."
Leave the Default Site and Site Link in Place
Do not rename or delete Default-First-Site-Name and DEFAULTIPSITELINK in the Active Directory. A Catch-22 situation exists between sites and site links. When you create a site, you must select a site link that it uses. Also, when you create a site link, you must select at least two sites that it connects. Leaving the defaults in place provides you with a staging area when adding sites and site links.
Creating Sites
Creating a site within the Active Directory Sites and Services MMC snap-in is quite easy. You simply right-click your mouse on the Sites container and select New. Type in the name of your new site and select a site link that it will use to connect it with other sites in your enterprise.
Knowing when to create a site is more difficult. There are only two requirements for creating sites:
All subnets within the site should be "well-connected." The physical links connecting these subnets should always be available. You do not want a site to contain subnets that are linked with a dial-up connection or a connection that is available only a few hours each day.
All subnets within the site should be connected via LANs. If you have multiple LANs connected with high-speed links, they are also good candidates for inclusion in a single site. Microsoft recommends that all subnets within the site be connected with links greater that 64 Kbps.
Based on your infrastructure and the needs of your organization, you should attept to find the correct balance between one site and many sites. Table 4.3.2 goes over some of the basic pros and cons of small versus large sites.
Table 4.3.2 Small Number of Sites Versus Large Numbes of Sites
Create site names from general to specific. For example, USA-AZ-Phoenix. Because sites are sorted alphabetically, this allows you to find them more easily in the Active Directory Sites and Services MMC snap-in.
Creating Subnets
In Windows 2000, a site is a collection of subnets. Also, subnets allow clients and servers to know what site they are in. For example, if you install a new Domain Controller, and the DC's subnet is already identified, that DC will be installed in the site that the subnet belongs to.
To create subnets in Windows 2000, do the following:
Run the Active Directory Sites and Services MMC snap-in.
Right-click the Subnet container and select New Subnet.
Enter the address of the subnet and the subnet mask.
Select the site that this subnet belongs to.
If your company groups subnets together at a physical location, you do not need to create subnet objects for every physical subnet. This can greatly simplify the subnet object maintenance in Windows 2000. For example, if the Boston office exclusively uses subnets beginning with 10.1.0.0, you can define a single subnet for that location. You do this by entering 10.1.0.0 as the subnet address and 255.255.0.0 as the subnet mask. This way, you can define one subnet for the entire location, rather than manually entering each physical subnet (10.1.1.0, 10.1.2.0, and so on).
Creating IP Site Links
After you decide that you need to implement multiple Windows 2000 sites, you need to plan how those sites will be connected. Inter-site transports, or site links, connect your sites and control replication and site coverage (if a Domain controller does not exist at a site).
Table 4.3.3 shows the items used to configure site links and their acceptable items.
Table 4.3.3 Configurable Items in IP Site Links
To create site links in Windows 2000, do the following:
Run the Active Directory Sites and Services MMC snap-in.
Select the Inter-Site Transports container to expand it.
Right-click the IP container and select New Site Link.
Enter the name of the site link and select at least two sites that will use this link.
Site links do not need to simply be point-to-point connections. It is possible for a site link to contain more than two sites. This is useful for reducing the number of site links that need to be created and managed. For example, if your company has three sites, each connected to one other with a T1, you can set up a single site link in which all three sites are members. This greatly simplifies the number of links that need to be created for large implementations.
Site Coverage
Not all sites in the Active Directory need to contain a Domain Controller. This is because of an important feature known as site coverage. By default, all Windows 2000 Domain Controllers will examine the sites and site links in the enterprise. The DC will then register itself in any site that does not already have a DC for that Domain.
This means that every site wil have a DC defined, by default, for every Domain in the enterprise, even if that site does not physically contain a DC for that Domain. The DCs that are published will be those from the "closest site" defined by the replication topology.
It is also possible to manually configure a DC to register in another site, regardless of the replication topology. This can be done by manually updating a Registry value on the Domain Controller that you want to register in another site. This is implemented with the SiteCoverage:REG_MULTI_SZ value in HKEY_LOCAL_MACHINE\ System\ CurrentControlSet\ Services\ Netlogon\ Parameters\.
Set this value to the name of the site or sites that you want this DC to register in. The site names exactly match the site names created in the Active Directory Sites and Services MMC snap-in. Within the SiteCoverage value, there must be only one site on each line.
Best Practices for Designing Your Active Directory Replication
Create sites based on collections of high-speed networks. You need to decide what determines a "high-speed" network, based on your needs.
Put DCs into those sites based on authentication and authorization needs. In some sites, it may be acceptable to use Domain Controllers in remote locations. However, be sure to assess the impact of a WAN outage.
Configure links based on the logical WAN to optimize replication between DCs.
Modifying the Active Directory Schema
The.
To allow updates to be made to the schema, you must do the following:
Configure your client to run the Active Directory Schema Manager MMC.
Use the Active Directory Schema MMC snap-in to change the Schema Operation Master to allow schema updates.
Be designated as a member of the Schema Administrators Global Security Group, which is located in the forest root.
Schema Modifications Are Permanent!
Schema modifications cannot be reversed and have serious implications throughout the Active Directory. After a class or attribute is added to the schema, it cannot be deleted, although it can be disabled.
Configure Your Client to Run the Active Directory Schema MMC Snap-in
The Active Directory Schema MMC is not installed by default on either Windows 2000 Professional Edition or Windows 2000 Server. To install the snap-in on Windows 2000 Professional, simply install the Administrative tools.
For instructions on installing the Administrative tools, see Chapter 3.3, "Using Administrative Tools."
On the Windows 2000 server family, you must enable the snap-in by registering the Schema Management Dynamic Linked Library (DLL). To do this, you need to run regsvr32.exe schmmgmt.dll from a command prompt.
After the Administrative tools are installed and enabled on your computer, you can then run MMC.exe and add the Active Directory Schema Console. Figure 4.3.2 shows an example of the Active Directory Schema MMC snap-in.
For more information on configuring the MMC console, see Chapter 3.2, "Using MMC Consoles."
Figure 4.3.2 Modifying the Windows 2000 schema using the MMC snap-in.
Use the Active Directory Schema MMC Snap-in to Change the Schema Operation Master to Allow Schema Updates
By default, all Domain Controllers prevent modifications on the schema. To modify the schema, you must configure the Schema Operations Master to allow updates. You accomplish this by executing the following steps:
Run the Active Directory Schema MMC snap-in.
Right-click the Active Directory Schema container.
Select Operations Master.
At the bottom of the Change Schema Master dialog box, select the checkbox to enable the option The Schema may be modified on this Domain Controller.
You will be able to do this only if you are a member of the Schema Admins Global Security group in the forest root.
The schema is also protected by a Windows 2000 Access Control List. By default, only members of the Schema Admins Global Security Group can make changes to the schema.
Where Should the Schema Admins Group Exist?
Because the Schema Admins group is a Global group, your account must exist in the forest root Domain. If your forest root Domain is in Windows 2000 Native mode, you can change this group to a Universal group, which can contain users from outside the local Domain.
For more information on Windows 2000 Groups, see Chapter 4.5, "Creating and Managing Groups."
Common Examples of Changes You Might Need to Make to the Schema
Although it is not recommended that you extend the schema (for example, add classes or attributes), it is sometimes necessary to change the properties of existing attributes. Even though these types of changes can be reversed, you should still plan carefully prior to making these changes.
There are two main types of schema changes that might be desirable to make:
Mark attributes for inclusion in the Global Catalog
Index attributes in the Active Directory:
Run the Active Directory Schema MMC snap-in.
Select the Attributes container.
Right-click the attribute you want to modify and select Properties.
Enable the Replicate this attribute to the Global Catalog checkbox.
Index Attributes in the Active Directory
The second type of change that may be desirable is to index attributes in the Active Directory. Doing so should increase the speed with with your Active Directory-enabled application can search that attribute.
To index an attribute in the Active Directory, do the following:
Run the Active Directory Schema MMC snap-in.
Select the Attributes container.
Right-click the attribute you want to modify and select Properties.
Enable the Index this attribute in the Active Directory checkbox.
Going Deeper: Restructing Domains
No
Move Objects Within a Domain
Moving objects within a Domain is the simplest of all restructuring activities. This functionality is built into the the Active Directory Users and Computers MMC snap-in. To move an object, right-click the object and select All Tasks; then choose Move. You will be presented with a list of containers within the Domain. Simply select the appropriate destination. Other MMC snap-ins also have this functionality for the objects they manage. For example, you can move Domain Controllers between sites in the Active Directory Sites and Services MMC snap-in.
Move Objects Between Domains in the Forest
To make it possible to move objects or collections of objects from one Domain in the forest to another, Microsoft provides the MOVETREE.EXE utility in the Windows 2000 Resource Kit.
MOVETREE.EXE commands can be quite complex. A complete list of parameters can be found by running MOVETREE.EXE /? or checking the Windows 2000 Resource Kit online documentation.
Before attempting to use MOVETREE.EXE, there are a couple of things that you need to do in advance. First, the destination Domain must be in Native mode. Second, the immediate parent of the object you are moving must exist. In the following example, the OU Executives must exist in the Domain mycompany.com.
Example of a Movetree Command
Situation: You need to move a single user object John Q. Public in the OU Finance from the Domain eur.mycompany.com to the OU Executives in the Domain mycompany.com:
Restructure Entire Domains
In Windows 2000, it is not possible to prune and graft Domains, either within a forest or between forests. However, it is possible to achieve the same end result with a little effort.
To make it possible to restructure Domains and to aid in the migration to Windows 2000, Microsoft has jointly developed the Active Directory Migration Tool (ADMT). This tool makes it possible to move all or part of a Domain to another location. For example, you can split Domains, consolidate Domains, or effectively move Domains by executing the following steps:
Create the target Domain in your forest.
Use the ADMT to migrate the objects from the source to the target.
Decommission the source Domain.
Create the Target Domain In Your Forest
One drawback of the ADMT is that you cannot perform an intact Domain move. The target Domain must exist in the Windows 2000 forest as a Native mode Domain. Follow the steps described earlier in this chapter to create the new Domain. This Domain will now be the destination for the objects that you are moving.
Note: This step is not necessary if you are consolidating Domains and at least one of them is in the Windows 2000 forest. Simply pick one of the Windows 2000 Domains in your forest as the target and migrate the other Domains' objects to that Domain.
Use the ADMT to Migrate the Objects from the Source to the Target
The ADMT provides major benefits over utilities such as MOVETREE when doing major Domain restructuring or migrations. These benefits include the following:
Task based MMC snap-in. The tool looks and behaves like other Windows 2000 tools.
Provides reporting and modeling tools. You have the ability to simulate migrations and view reports. Reports are saved as HTML files to allow them to be posted to your intranet.
Provides group synchronization. Without this tool, you would be required to migrate an entire closed set. Closed sets are collections of users and groups that can be moved without cloning. It is possible that the smallest closed set is the entire Domain. For example, due to the rules of group membership, you cannot move a Global group until all members of that group are in the destination Domain. Also, you cannot move users without moving their Global groups.
ADMT continues the operation, even if there are individual failures. This prevents a single failure from causing the entire operation to fail.
For more information on the ADMT, see the Microsoft Web site at.
Decommission the Source Domain
If desired, you can decommission the source Domain. If this Domain is part of your Windows 2000 forest, you need to run the Active Directory Wizard on each of the Domain Controllers to uninstall the Active Directory. On the last Domain Controller (preferably the one that owns the PDC FSMO), you will specify that this is the last DC in this Domain. This will remove all references of that Domain from the Active Directory.
This step is not necessary if you are splitting Domains and the source Domain is in the Windows 2000 forest. For example, if you want to split a Domain in half, you could migrate half of the objects to the new Domain and leave half in the current Domain. | https://www.informit.com/articles/article.aspx?p=131008&seqNum=4 | CC-MAIN-2021-49 | refinedweb | 3,673 | 56.25 |
In this tutorial, I will explain the fundamentals of java classes and objects.
Java is an object-oriented programming language. This means, that everything in Java, except the primitive types is an object. But what is an object at all? The concept of using classes and objects is to encapsulate state and behavior into a single programming unit. This concept is called encapsulation. Java objects are similar to real-world objects. For example, we can create a car object in Java, which will have properties like current speed and color; and behavior like: accelerate and park.
Creating a Class
Java classes are the blueprints of which objects are created. Let’s create a class that represents a car.
public class Car { int currentSpeed; String name; public void accelerate() { } public void park() { } public void printCurrentSpeed() { } }
Look at the code above. The car-object states (current speed and name) are stored into fields and the behavior of the object (accelerate and park) is shown via methods. In this example the methods are accelerate(), park() and printCurrentSpeed().
Let us implement some functionality into those methods.
1. We will add 10 miles per hour to the current speed of the car each time we call the accelerate method.
2. Calling the park method will set the current speed to zero
3. printCurrentSpeed method will display the speed of the car.
To implement these three requirements we will create a class named Car and store the file as Car.java
public class Car { int currentSpeed; String name; public Car(String name) { this.name = name; } public void accelerate() { // add 10 miles per hour to current speed currentSpeed = currentSpeed + 10; } public void park() { // set current speed to zero currentSpeed = 0; } public void printCurrentSpeed() { // display the current speed of this car System.out.println("The current speed of " + name + " is " + currentSpeed + " mpH"); } }
Class Names
When you create a java class you have to follow this rule: the file name and the name of the class must be equal. In our example – the Car class must be stored into a file named
Car.java . Java is also case-sensitive: Car, written with capital C is not the same as car, written with lower-case c.
Java Class Constructor
Constructors are special methods. Those are called when we create a new instance of the object. In our example above the constructor is:
public Car(String name) { this.name = name; }
Constructors must have the same name as the class itself. They may take parameters or not. The parameter in this example is “name”. We create a new car object using this constructor like this (I will explain this in more detail later in this tutorial):
Car audi = new Car("Audi");
Java Comments
Did you noticed the // marker in-front of lines 11, 16 and 21? This is how we write comments in Java. Lines marked as comment will be ignored while executing the program. You can write comments to give additional explanation of what is happening in your code. Writing comments is a good practice and will help others to understand your code. It will also help you when you come back later to your code.
Creating Objects
Now lets continue with our car example. We will create a second class named CarTest and store it into a file named CarTest.java
public class CarTest { public static void main(String[] args) { // create new Audi car Car audi = new Car("Audi"); // create new Nissan car Car nissan = new Car("Nissan"); // print current speed of Audi - it is 0 audi.printCurrentSpeed(); // call the accelerate method twice on Audi audi.accelerate(); audi.accelerate(); // call the accelerate method once on Nissan nissan.accelerate(); // print current speed of Audi - it is now 20 mpH audi.printCurrentSpeed(); // print current speed of Nissan - it is 10 mpH nissan.printCurrentSpeed(); // now park the Audi car audi.park(); // print current speed of Audi - it is now 0, because the car is parked audi.printCurrentSpeed(); } }
In the code above we first create 2 new objects of type Car – Audi and Nissan. This are two separate instances of the class Car (two different objects) and when we call the methods of the Audi object this does not affect the Nissan object.
The result of executing CarTest will look like this:
The current speed of Audi is 0 mpH The current speed of Audi is 20 mpH The current speed of Nissan is 10 mpH The current speed of Audi is 0 mpH
I encourage you to experiment with the code. Try to add a new method to the Car class or write a new class.
In our next tutorial you will learn more about the concepts of Object Oriented Programming. | https://javatutorial.net/java-objects-and-classes-tutorial | CC-MAIN-2020-40 | refinedweb | 778 | 64.41 |
Odoo Help
Odoo is the world's easiest all-in-one management software. It includes hundreds of business apps:
CRM | e-Commerce | Accounting | Inventory | PoS | Project management | MRP | etc.
How to count how many products are in a report?
I have a report on the account.invoice model and want to show how many products in the invoice line. Below will show a picture of what I want to do.
Image:
The idea is to count how many products there are on the invoice and return the number of the quantity of products.
Maybe it may be simple, but really do not know everything about Odoo.
Thanks for your advice and help.
I try to query into report, it's working...
class customer_report(models.Model):
_name = "customer.report"
_description = "Orders Statistics"
_auto = False
name = fields.Many2one('res.partner', readonly=True)
p_id = fields.Many2one('preorder.config','PreOrder Ref')
tot_product = fields.Integer('# of Unique Product')
tot_piece = fields.Integer('# of Piece')
def init(self, cr):
"""Initialize the sql view for the event registration """
tools.drop_view_if_exists(cr, 'customer_report')
# TOFIX this request won't select events that have no registration
cr.execute(""" CREATE VIEW customer_report AS (
poc.id::varchar || '/' || coalesce(poc.id::varchar,'') AS id,
poui.customer AS p_id,
poui.partner_id AS name,
count(pl.product_id) AS tot_product,
count(poc.id) AS tot_piece
from
preorder_config poc
left join preorder_user_input poui on (poui.preorder_id = poc.id)
left join preorder_product_rel ppr on (ppr.preorder_id = poc.id)
left join preorder_user_input_product_line pl on (pl.user_input_id = poui.id)
group by
poc.id, poui.preorder_id, poui.partner_id
)
""")
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Can You post your code ? | https://www.odoo.com/forum/help-1/question/how-to-count-how-many-products-are-in-a-report-100190 | CC-MAIN-2018-17 | refinedweb | 287 | 62.75 |
04-28-2015 08:25 AM
The LWIP library included with Xilinx SDK 2014.4 has a problem with handling of received packets.
It seems to be a related to handling of the memory cache. The problem manifests through
byte-swapped port numbers appearing in tcp_input(). Affected packets are skipped, and LWIP
sends out TCP-RST packets for these invalid packets.
Of course the TCP protocol will recover from the data loss, but the data rate drops
down to 20-50 Mbit/sec - fairly low for a 1GB/s ethernet connection.
The problem can be easily reproduced on a ZC702 Board with the
Echo Server template applications from SDK and a few patches that are described here.
I have included the patched files for reference.
Also included is a small Winsock PC application that connects to
the echo server at port 7, continuously sends data and prints the achieved
data rate on the console.
=== Steps to recreate the Project from scratch ====
- run Xilinx SDK 2014.4, point it to an empty folder as workspace.
- create a new "lwIP Echo Server" Application for the ZC702 board.
Apply the following patches:
in echo.c, the following patches are necessary:
add this function somewhere before recv_callback:
void store_payload( const char* payload, unsigned int len )
{
static char buffer[100*1024];
static int index = 0;
if( payload==NULL ) { while(1){} }
if( len > 2*1024 ) { while(1){} }
if( sizeof(buffer)-index < len )
{
index = 0;
}
memcpy( buffer+index, payload, len );
index += len;
}
This function is used to actually store the data from recv_callback
into memory. A 100kB circular buffer is used to create a memory access
pattern that triggers the caching bug more often.
in echo.c, in recv_callback: replace this line:
err = tcp_write(tpcb, p->payload, p->len, 1);
with this one:
store_payload( p->payload, p->len );
This is used to store the data in memory instead of echoing it back.
in echo.c, in recv_callback():
replace this line:
tcp_recved(tpcb, p->len);
with this:
tcp_recved(tpcb, p->tot_len);
This actually fixes another unrelated bug in the echo server template,
that can cause tcp receive window congestion.
It's recommended to fix this bug with the line above, otherwise it
makes tracing the real caching bug more difficult.
in system.mss, in the section on lwip:
Remove the DHCP parameters, and add the following parameters:
PARAMETER mem_size = 524288
PARAMETER memp_n_pbuf = 2048
PARAMETER memp_n_tcp_pcb = 1024
PARAMETER memp_n_tcp_seg = 1024
PARAMETER n_rx_descriptors = 256
PARAMETER n_tx_descriptors = 256
PARAMETER pbuf_pool_size = 4096
PARAMETER tcp_debug = true
PARAMETER tcp_snd_buf = 65535
PARAMETER tcp_wnd = 65535
These parameters taken from XAPP1026.
Then, click "Re-generate BSP Sources", to actually apply these parameters.
The automatic rebuild is not sufficient!
These parameters are required for the caching bug to occur more often.
They are taken from XAPP1026.
NOTE: While it is possible to tweak the settings such that the bug no longer
occurs (e.g. by setting tcp_wnd to 10000), the bug is still there and
will occur in applications with more complex memory access patterns.
in bsp/ps7_cortexa9_0/libsrc/lwip140_v2_3/src/lwip-1.4.0/src/core/tcp_in.c:
search for this loop (easily found by searching for the string "destined"):
for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next)
Right before this loop, add the following code:
if( tcphdr->dest == 0x700 )
{
xil_printf( "byte-flipped port address: expected:0x0007 got:0x0700\n");
}
Do NOT "re-generate the BSP sources", otherwise this patch is lost.
The printf you added her should never be triggered, but it will be,
exposing the caching problem.
It appears that a previously already processed packet from the cache is visible,
since port numbers are byte-flipped from big endian to little endian order in tcp_input().
Run the test:
Connect the ZC702 board via Gbit-Ethernet cable to a PC, configure the PC IP
in the same subnet (e.g. 192.168.1.200).
Connect a UART console, and run the application.
Use the included PC application to connect to the Board on TCP Port 7,
and continuously send data to it. Note: The included PC Application is just an
example - any application that connects to 192.168.1.10 on TCP-Port 7 and
spams the server with data will do.
After the data transfer is started, you will get following lines
in the UART console after about 2 seconds:
(...)
Board IP: 192.168.1.10
Netmask : 255.255.255.0
Gateway : 192.168.1.1
TCP echo server started @ port 7
byte-flipped port address: expected:0x0007 got:0x0700
byte-flipped port address: expected:0x0007 got:0x0700
byte-flipped port address: expected:0x0007 got:0x0700
byte-flipped port address: expected:0x0007 got:0x0700
...
The PC application console shows high fluctuations in data rate:
net_init : 1
net_init : 2
net_init : 2.1
net_init : 2.2
net_init : 3
connected.
connection established. sending...
2 Data Rate MBit/sec : 155.7 mean=155.67
4 Data Rate MBit/sec : 123.5 mean=137.75
6 Data Rate MBit/sec : 88.4 mean=116.16
8 Data Rate MBit/sec : 106.4 mean=113.56
10 Data Rate MBit/sec : 233.2 mean=126.54
12 Data Rate MBit/sec : 137.8 mean=128.29
14 Data Rate MBit/sec : 270.8 mean=138.72
16 Data Rate MBit/sec : 129.3 mean=137.46
18 Data Rate MBit/sec : 129.3 mean=136.50
20 Data Rate MBit/sec : 233.2 mean=142.41
To fix this caching problem and prove that it's caching related, add this to main.c:
#include "xil_cache.h"
and at the beginning of main():
Xil_DCacheDisable();
The performance drops considerably, but no more byte-swapping will occur.
UART console:
(...)
Board IP: 192.168.1.10
Netmask : 255.255.255.0
Gateway : 192.168.1.1
TCP echo server started @ port 7
PC Application Console:
net_init : 1
net_init : 2
net_init : 2.1
net_init : 2.2
net_init : 3
connected.
connection established. sending...
2 Data Rate MBit/sec : 178.8 mean=178.82
4 Data Rate MBit/sec : 168.0 mean=173.26
6 Data Rate MBit/sec : 175.0 mean=173.84
8 Data Rate MBit/sec : 186.7 mean=176.89
10 Data Rate MBit/sec : 182.6 mean=177.99
12 Data Rate MBit/sec : 182.8 mean=178.78
14 Data Rate MBit/sec : 182.6 mean=179.31
16 Data Rate MBit/sec : 175.0 mean=178.75
18 Data Rate MBit/sec : 168.0 mean=177.50
20 Data Rate MBit/sec : 171.6 mean=176.89
22 Data Rate MBit/sec : 182.6 mean=177.39
24 Data Rate MBit/sec : 171.3 mean=176.87
26 Data Rate MBit/sec : 178.8 mean=177.01
28 Data Rate MBit/sec : 178.8 mean=177.14
Can anyone check this and confirm this problem?
And will it be fixed any time soon, making LWIP more reliable on zynq?
09-01-2016 05:59 PM
I saw no response to this post which is disappointing as this must affect many users, although most may not be aware, and IS STILL A PROBLEM in the lwip stack supplied with Vivado 2016.1!!!
Below is a simpler way to replicate with the hope that Xilinx addresses this issue as it directly affects a Xilinx provided Example.
I saw another post on a different site noting a different issue caused by this same problem with the same ultimate but undesirable solution of disabling the Data cache.
This issue can basically be replicated by simply building the Lwip demo echo server and then pinging it. About every other packet will get dropped (or not understood) and await the retry a second later making ping times jump from under a ms to a second.
If you add the same Xil_DCacheDisable() that you note in your post the issue goes away. Sort of proving that it is related to cache issues.
Hopefully this can get addressed quickly!!
07-07-2017 08:59 AM | https://forums.xilinx.com/t5/Embedded-Development-Tools/LwIP-library-on-Zynq-broken/m-p/595268 | CC-MAIN-2020-29 | refinedweb | 1,316 | 66.84 |
Customize Tags
Tags are key/value string pairs that are both indexed and searchable. Tags power features in sentry.io such as filters and tag-distribution maps. Tags also help you quickly both.
You'll first need to import the SDK, as usual:
import * as Sentry from "@sentry/node";
Define the tag:
Sentry.setTag("page_locale", "de-at");
Some tags are automatically set by Sentry. We strongly recommend against overwriting those tags. Instead, name your tags with your organization's nomenclature.
Once you've started sending tagged data, you'll see it when logged in to sentry.io. There, you can view the filters within the sidebar on the Project page, summarized within an event, and on the Tags page for an aggregated event.
Our documentation is open source and available on GitHub. Your contributions are welcome, whether fixing a typo (drat!) to suggesting an update ("yeah, this would be better"). | https://docs.sentry.io/platforms/node/guides/connect/enriching-events/tags/ | CC-MAIN-2021-31 | refinedweb | 150 | 69.18 |
#include <iostream.h>
#include <stdlib.h>
int main()
{
int j;
char k[4]= "123";
j = static_cast<int>( k[0]);
cout<<j<<endl;
system("PAUSE");
return 0;
}
I am writing a program where i receive a string with numbers in it. My program has to validate those numbers. I try to cast the numbers to an intiger for easier validation.
This program will run om win. using Borland.
The problem i'm having is that j contains the dec value of of 1.
I want j to comtain the number 1 not the decimal value of 1.
How do i do that. | http://cboard.cprogramming.com/cplusplus-programming/5941-problem-casting.html | CC-MAIN-2015-22 | refinedweb | 101 | 76.72 |
![endif]-->
Arduino LCD playground | LCD 4-bit library
Please note that from Arduino 0016 onwards the official LiquidCrystal library built into the IDE will also work using 6 Arduino Pins in 4 bit mode. It is also faster and less resource hungry, and has more features. This LCD4bit library dates from 2006 when the official library only worked in 8 bit mode. It is effectively redundant.
This was an unofficial, unmaintained Arduino library which allowed your Arduino to talk to a HD44780-compatible LCD using only 6 Arduino pins. It was neillzero's conversion of the code from Heather's original Arduino LCD tutorial which required 11 Arduino pins.
Nowadays, it is recommended to use the LiquidCrystal library that comes with Arduino IDE.
Download the old library! (includes an example sketch).
This library should work with all HD44780-compatible devices. It has been tested successfully with:
Install exactly as you would the LiquidCrystal library in the original LCD tutorial. For a basic explanation of how libraries work in Arduino read the library page.
The library is intended to be a 4-bit replacement for the original LCD tutorial code and is compatible with very little change. Here's what you must do after the setup described in the original tutorial:
The pin assignments for the data pins are hard coded in the library. You can change these but it is necessary to use contiguous, ascending Arduino pins for the library to function correctly. To change this behavior to be able to use any Arduino pins, change these lines:
for (int i=DB[0]; i <= DB[3]; i++) { digitalWrite(i,val_nibble & 01);
to
for (int i=0; i <= 3; i++) { digitalWrite(DB[i],val_nibble & 01);
LCD4Bit lcd = LCD4Bit(1);
#include <LCD4Bit.h> LCD4Bit lcd = LCD4Bit(1); //create a 1-line display. lcd.clear(); delay(1000); lcd.printIn("arduino");
There's also a working, commented example sketch included in the download, in LCD4Bit/examples/LCD4BitExample/LCD4BitExample.pde
I also added a couple of functions to stimulate ideas, but you might want to delete them from your copy of the library to save program space.
//scroll entire display 20 chars to left, delaying 50ms each step
lcd.leftScroll(20, 50);
//move to an absolute position
lcd.cursorTo(2, 0); //line=2, x=0.
If you have never had your LCD working, I suggest you start with the original arduino LCD tutorial, using all 8-bits in the data-bus. Once you are sure your display is working, you can move on to use the 4-bit version.
I've created a googlecode project to maintain the source, at
This does not yet have changes from other contributors.
You can get the source from svn anonymously over http using this command-line:
svn checkout arduino-4bitlcd
See this forum post. Specifically, note that you should delete the library's .o file after change, so that it will be recompiled.
LCD4Bit development notes
the main LCD playground page and the original LCD tutorial.
A speed tuned version with assembler: LCD4Bit with Assembler = Highspeed LCD | http://playground.arduino.cc/Code/LCD4BitLibrary | CC-MAIN-2016-50 | refinedweb | 509 | 64.61 |
Get Swifty cryptography everywhere
Update: Cory Benfield from Apple has confirmed that on Apple's platforms SwiftCrypto is limited to those that support CryptoKit, and can't act as a polyfill for older releases such as iOS 11/iOS 12 and macOS 10.14. However, there's hope that might change – Cory added "we’d be happy to discuss that use-case with the community." In theory that could mean we get SwiftCrypto support for iOS 12 and earlier, which would be awesome!
Apple today released SwiftCrypto, an open-source implementation of the CryptoKit framework that shipped in iOS 13 and macOS Catalina, allowing us to use the same APIs for encryption and hashing on Linux.
The release of SwiftCrypto is a big step forward for server-side Swift, because although we’ve had open-source Swift cryptography libraries in the past this is the first one officially supported by Apple. Even better, Apple states that the “vast majority of the SwiftCrypto code is intended to remain in lockstep with the current version of Apple CryptoKit,” which means it’s easy for developers to share code between Apple’s own platforms and Linux.
What’s particularly awesome about SwiftCrypto is that if you use it on Apple platforms it effectively becomes transparent – it just passes your calls directly on to CryptoKit. This means you can write your code once using
import Crypto, then share it everywhere. As Apple describes it, this means SwiftCrypto “delegates all work to the core implementation of CryptoKit, as though SwiftCrypto was not even there.”
The only exception here is that SwiftCrypto doesn’t provide support for using Apple’s Secure Enclave hardware, which is incorporated into devices such as iPhones, Apple Watch, and modern Macs. As the Secure Enclave is only available on Apple hardware, this omission is unlikely to prove problematic.
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SwiftCrypto is available today, so why not give it a try?
If you’re using Xcode for your project, go to File > Swift Packages > Add Package Dependency to get started; if not, you can just edit the Package.swift file directly. Either way, you should make it point towards then choose “Up To Next Major”.
Once Xcode has downloaded the package (or if you’ve run swift package fetch from the command line), you can write some code to try it out.
For example, this will compute the SHA256 hash value of a string:
import Crypto let inputString = "Hello, SwiftCrypto" let inputData = Data(inputString.utf8) let hashed = SHA256.hash(data: inputData)
If you want to read that back as a string – for example, if you want to print the SHA so users can verify a file locally – you can create it like this:
let hashString = hashed.compactMap { String(format: "%02x", $0) }.joined()
For more information on SwiftCrypto read the official Swift.org announcement or check out the project. | https://www.hackingwithswift.com/articles/211/apple-announces-swiftcrypto-an-open-source-implementation-of-cryptokit | CC-MAIN-2022-40 | refinedweb | 522 | 60.65 |
This is the mail archive of the libstdc++@sources.redhat.com mailing list for the libstdc++ project.
Phil Edwards wrote: > > To implement things like std::random_shuffle, the code in bits/stl_algo.h > calls __random_number, which in turn calls either the standard rand(), > or the non-standard-but-cooler lrand48(), depending on if __STL_NO_DRAND48 > has been #define'd or not in stl_config.h. > > These RNGs use different functions for seeding, however. The first uses > srand(), the second uses srand48(). Seeding with one function has no > effect if you happen to be using the "other" flavor of generator. > > Add to this the observations that: > > 1) Most people only know to call srand(), > 2) Most modern systems will have the 48-bit generator available, > 3) Nowhere in the implementation do we make any mention of the seeding > functions, other than the the 'using' statement for srand(), > > and you can see a problem shaping up. Users who seed with srand() and use > random_shuffle() are going to be surprised when they get the same results > over and over even though the seeds being used are different. Their only > recourse is to dig into the guts of the library to find the conditional > compilation using __STL_NO_DRAND48, and then use that in their own code > to conditionally compile srand or srand48. > > Anybody have any thoughts as to alleviate this? Maybe provide some > seed_random() wrapper around the seeders that performs the same conditional > compilation? Surely somebody has used random_shuffle before and solved > this already? What do they use at SGI? IMHO those who realy need "random" random use thier own random generator (random_shuffle has a version which get a random generator) or know about srand48 (look into the code) those who just need "some" random generator the deafult may be good. anyway I think it'd be good to put srand48 into namespace std as srand on platform which support it and those who realy use c++ eg. <cstdlib> find that srand and don't have to care about it. > Phil > (Yes, I did find this out the hard way. :-) me too:-( but the worst is that random generator in standard algorithm passed as value (!!!) and not by reference, when you've got a good random generator is more difficult find out:-( -- Levente "The only thing worse than not knowing the truth is ruining the bliss of ignorance." | http://gcc.gnu.org/ml/libstdc++/2000-08/msg00015.html | crawl-002 | refinedweb | 390 | 60.85 |
JMX Namespaces now available in JDK 7
The JMX Namespace feature has now been integrated into the JDK 7 platform. You can read about it in detail in the online documentation for javax.management.namespace. Here's my quick summary.
Namespaces add a hierarchical structure to the JMX naming scheme. The easiest way to think of this is as a directory hierarchy. Previously JMX MBeans had names like
java.lang:type=ThreadMXBean. Those names are still legal, but there can now also be names like
othervm//java.lang:type=ThreadMXBean.
The
othervm "directory" is a
JMXNamespace. You create it by registering a
JMXNamespace MBean with the special name
othervm//:type=JMXNamespace. You specify its contents via the
sourceServer argument to the
JMXNamespace constructor.
There are three typical use cases for namespaces. First, if you have more than one MBean Server in the same Java VM (for example, it is an app server, and you have one MBean Server per deployed app), then you can group them all together in a higher-level MBean Server. Second, if you have MBean Servers distributed across different Java VMs (maybe on different machines), then again you can group them together into a "master" MBean Server. Then clients can access the different MBean Servers without having to connect to each one directly. Finally, namespaces support "Virtual MBeans", which do not exist as Java objects except while they are being accessed.
There's much more to namespaces than I've described here. Daniel Fuchs is the engineer who did most of the design and implementation work on namespaces, and I expect he will have more to say about them in the near future on his blog.
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- emcmanus's blog
- 3191 reads | https://weblogs.java.net/blog/emcmanus/archive/2008/09/jmx_namespaces.html | CC-MAIN-2015-35 | refinedweb | 294 | 64.3 |
is it possible store in EXIST an XML document in physical chunks =
using the <!ENTITY name SYSTEM "filename"> declaration ?
Using Exist Administrator interface, I before uploaded this fragment =
(fragment.xml) in Exist root (/db):
<DocumentoNIR nome=3D"DecretoLegislativo ">
<meta>
<descrittori>
<pubblicazione tipo=3D"GU" norm=3D"19940519" num=3D"115"/>
<urn>urn:nir:stato:decreto.legislativo:1994-04-16;297</urn>
<vigenza id=3D"v1" inizio=3D"20000901"/>
</descrittori>
</meta>
</DocumentoNIR>
But when I try to upload the master document:
<?xml version=3D"1.0" encoding=3D"UTF-8"?>
<!DOCTYPE NIR SYSTEM =
""; [
<!ENTITY fragment SYSTEM "/db/fragment.xml">
]>
<NIR tipo=3D"originale" xmlns=3D"">
&fragment;
</NIR>
Exist answer :
Error: \db\fragment.xml (Impossible to find the specified path)
******
If I change the ENTITY declaration with an absolute URL enclosed:
<!ENTITY fragment
Exist answer
Error: The element type "META" must be terminated by the matching =
end-tag "</META>".
What is the problem ?
eXist does not preserve entity declarations and references for several=20
reasons: The db uses SAX to parse the doc and the SAX parser will always =
try=20
to resolve entities. Thus fragment.xml will be included into the SAX stre=
am=20
of the master document and eXist will not see the entity reference. This=20
means that you are trying to store fragment.xml two times: one time as=20
fragment.xml and another time inside the master document.
It would be possible to enhance eXist to preserve entities: As a first st=
ep we=20
could replace SAX by Xerces XNI, which would give us more control over th=
e=20
parse process and allow us to store entities and entity references as nod=
e=20
objects. But this would also imply that doctype declarations (external _a=
nd_=20
internal) have to be preserved to keep the doc valid, which is not that e=
asy.
> <!ENTITY fragment SYSTEM
> "">
This should basically work (though I don't think it makes much sense - se=
e=20
above) and I'm not sure why the parser complains. Are all your tags corre=
ctly=20
defined in the DTD?
If your data is to large to be stored as a single document, there may be =
other=20
ways to split it, e.g. by using some kind of identifier in the master to=20
reference the parts.
Cheers,
Wolfgang
Wolfgang and Greg, thank you for the detailed answers.
I think it could be useful introduce ENTITY declaration if the content of a
fragment has to be made reusable in several XML document without replicate
it and creating a dynamic XML native consistence without any
post-processing. Another interesting use it could be getting parallel
locking and authoring of different fragments in the same XML document.
Obviously, it makes sense if the database preserve entities.
Another solution, that also expand the possible uses, is a "shortcut"
database facility or, using an XIndice term, an "Autolinking" facility,
automating links between documents. This allows you to break out duplicate
data into shared documents or include a dynamic element such as the output
of a query or XMLObject invocation into an XML file stored in the
repository.
For example, XIndice "AutoLinking" is specified by adding special attributes
( in namespace) to the XML tag
defining the link. These attributes are intercepted from the database when
the XML document enclosing them is fetched (for example using an XPATH
query) and one the following mechanisms is activated:
1.. replace - Replaces the linking element with the content of the href
URI
2.. content - Replaces all child content of the linking element with the
content of the href URI. The linking element is not replaced.
3.. append - Appends the content of the href URI to the content of the
linking element.
4.. insert - Inserts the content of the href URI as the first child of the
linking element.
The "shortcut" facility could be also implemented integrating the database
with a W3C XLink parser and using "simple" xlink with "show" attribute. For
example the "embed" value instancing the "show" attribute allows an
expand-in-place behaviour:
<my:crossReference
xmlns:my="";
xmlns:xlink="";
xlink:type="simple"
xlink:href="fragment.xml"
xlink:show="embed"
xlink:
Bye,Giampiero
----- Original Message -----From: "Wolfgang Meier"
<meier@...>To: <exist-open@...>Sent:
Tuesday, September 24, 2002 1:28 PMSubject: Re: [Exist-open] ENTITY SYSTEM -
Breaking an XML document in chunkseXist does not preserve entity
declarations and references for severalreasons: The db uses SAX to parse the
doc and the SAX parser will always tryto resolve entities. Thus fragment.xml
will be included into the SAX streamof the master document and eXist will
not see the entity reference. Thismeans that you are trying to store
fragment.xml two times: one time asfragment.xml and another time inside the
master document.It would be possible to enhance eXist to preserve entities:
As a first stepwecould replace SAX by Xerces XNI, which would give us more
control over theparse process and allow us to store entities and entity
references as nodeobjects. But this would also imply that doctype
declarations (external _and_internal) have to be preserved to keep the doc
valid, which is not thateasy.> <!ENTITY fragment SYSTEM>
"">This should basically
work (though I don't think it makes much sense - seeabove) and I'm not sure
why the parser complains. Are all your tagscorrectlydefined in the DTD?If
your data is to large to be stored as a single document, there may
beotherways to split it, e.g. by using some kind of identifier in the master
toreference the parts.Cheers,Wolfgang
Thanks a lot for your suggestions and ideas. I guess, implementing either=
=20
XIndice "AutoLinking" or simple XLink should not be too difficult. Class=20
org.exist.storage.Serializer (and NativeSerializer) could be extended to=20
process XLink attributes during the serialization of the document. Using =
the=20
methods defined there, we may insert arbitrary document fragments into th=
e=20
generated SAX stream.=20
I have not studied the XLink specification in depth, but I guess we could=
=20
start with a limited subset. We should be able to implement the=20
expand-in-place example you presented in rather short time (however, I ha=
ve=20
to stop myself - there's other work waiting to be finished, so I'm trying=
to=20
keep my hands off the code :-).
Thanks,
Wolfgang | https://sourceforge.net/p/exist/mailman/message/5621117/ | CC-MAIN-2017-43 | refinedweb | 1,055 | 53.81 |
サービス AdWords API Reference type UrlData (v201809) Service AdGroupAdService AdService Dependencies Ad ▼ UrlData Holds a set of final urls that are scoped within a namespace. Namespace Field urlId xsd:string Unique identifier for this instance of UrlData. Refer to the Template Ads documentation for the list of valid values. This field is required and should not be null when it is contained within Operators : ADD. This string must not be empty, (trimmed). finalUrls UrlList A list of final landing page urls. finalMobileUrls UrlList A list of final mobile landing page urls. trackingUrlTemplate xsd:string URL template for constructing a tracking URL. 30, 2019 | https://developers.google.cn/adwords/api/docs/reference/v201809/AdGroupAdService.UrlData?hl=ja | CC-MAIN-2019-35 | refinedweb | 103 | 58.69 |
The LCD is a frequent guest in Arduino projects. But in complex circuits, we may have a lack of Arduino ports due to the need to connect a screen with many pins. The way out in this situation can be the I2C/IIC adapter, which connects the almost standard Arduino 1602 shield to the Uno, Nano, or Mega boards with only four pins. This article will see how you can connect the LCD screen with an I2C interface, what libraries can be used, write a short example sketch, and break down typical errors.
Arduino LCD 1602
The LCD 1602 Liquid Crystal Display is a good choice for displaying character strings in various projects. It is inexpensive, there are different backlight colors, and you can easily download ready-made libraries for Arduino sketches. But the most important disadvantage of this screen is the fact that the display has 16 digital pins, of which at least six are mandatory. So using this LCD screen without i2c adds serious limitations for Arduino Uno or Nano boards. If the pins are not enough, you will have to buy an Arduino Mega board or save the pins by connecting the display via I2C, among other things.
Short Description of the LCD 1602 Pins
Let’s take a closer look at the pins of LCD1602:
Each of the pins has a different function:
1. Ground GND;
2. Power 5V;
3. Contrast setting of the monitor;
4. Command, Data;
5. Write and read data;
6. Enable;
7-14. Data Lines;
15. Illumination Plus;
16. Minus backlight.
Display Specifications:
- Symbol display type, there is an option to load symbols;
- LED backlight;
- Controller HD44780;
- The supply voltage of 5V;
- Format 16h2 characters;
- Operating temperature range from -4F to +158F, storage temperature range from -22F to +176F;
- The viewing angle is 180 degrees.
Diagram of LCD Connection to Arduino Board Without I2C
The standard circuit for connecting the monitor directly to an Arduino microcontroller without I2C is as follows.
Because of the number of pins you have to connect, you may not have enough space to connect all the parts you need. Using I2C reduces the number of wires to 4 and the occupied pins to 2.
Description of the I2C Protocol
Before discussing connecting the display to the Arduino with an i2C adapter, let’s talk briefly about the i2C protocol itself.
I2C/IIC (Inter-Integrated Circuit) – is a protocol originally created to communicate integrated circuits in an electronic device. The development belongs to Philips. The i2c protocol is based on an 8-bit bus, which is needed to link the blocks in the control electronics, and an addressing system that allows you to communicate on the same wires with multiple devices. We simply send data back and forth to one device or the other, adding the desired item’s ID to the data packets.
The simplest I2C circuit can have one master device (most often an Arduino microcontroller) and several slaves (such as an LCD). Each device has an address in the range of 7 to 127. There must not be two devices with the same address in one circuit.
The Arduino board supports I2C at the hardware level. You can use pins A4 and A5 to connect devices using this protocol.
There are several advantages to I2C operation:
- Only two lines are required for operation – SDA (data line) and SCL (clock line).
- Connection of a large number of master devices.
- Reduced development time.
- Only one microcontroller is required to control the whole set of devices.
- The possible number of microchips that can be connected to one bus is limited only by the capacity limit.
- High data integrity because of the special surge-suppression filter built into the circuits.
- Easy diagnosis of failures that occur and quick troubleshooting.
- The bus is already integrated into the Arduino itself, so there is no need to develop an additional bus interface.
Disadvantages:
- There is a capacitive limitation on the line – 400 pF.
- Difficult to program the I2C controller if there are several different devices on the bus.
- With a large number of devices, there is difficulty locating a failure if one of them sets the low-level state incorrectly.
I2C Module for the Arduino LCD 1602
The fastest and most convenient way to use the I2C display in the Arduino is to buy a ready-made screen with built-in protocol support. But there are not many of them, and they are not cheap. But a variety of standard screens have already been released in huge numbers. Therefore, the most affordable and popular option today is to buy and use a separate I2C module – adapter, which looks like this:
On one side of the module, we see I2C pins – ground, power, and 2 for data transfer. On the other side of the adapter, we see external power connectors. Of course, there are many pins on the board, with which the module is soldered to the standard pins of the screen.
The i2c outputs are used to connect to the Arduino board. If needed, we connect an external power supply for the backlight. With the built-in trim resistor, we can adjust the adjustable contrast value J.
You can find LCD 1602 modules with already soldered adapters on the market, and they are as simple as possible to use. If you bought a separate adapter, you have to solder it to the module beforehand.
Connecting the LCD Screen to the Arduino via I2C
To connect, you need the Arduino board itself, the display, a breadboard, connecting wires, and a potentiometer.
If you use a special separate I2C adapter, you need to first sell it to the screen module. It’s hard to make a mistake there, and this diagram can guide you.
The I2C enabled liquid crystal screen is connected to the board with four wires – two wires for data, two wires for power.
- The GND pin connects to GND on the board.
- The VCC pin is connected to 5V.
- SCL is connected to pin A5.
- SDA is connected to pin A.
And that’s it! No cobwebs of wires that are very easy to get tangled in. That said, we can simply leave all the complexity of the i2C protocol implementation to the libraries.
Libraries for Working with the I2C LCD
To interface the Arduino with the LCD 1602 via the I2C bus, you need at least two libraries:
- The Wire.h library for I2C communication is already in the standard Arduino IDE program.
- The LiquidCrystal_I2C.h library, which includes a large variety of commands for controlling the monitor via the I2C bus and allows you to make your sketch easier and shorter. You need .to install the library LiquidCrystal_I2C.h after connecting the display additionally
After connecting all the necessary libraries to the sketch, we create an object and can use all its functions. For testing, let’s load the following standard sketch from the example.
#include <Wire.h> #include <LiquidCrystal_I2C.h> // Connection of the library // #include <LiquidCrystal_PCF8574.h> // Connection of alternative library LiquidCrystal_I2C lcd(0x27,16,2); //Indicate I2C address (the most common value), as well as screen parameters (in case of LCD 1602 - 2 lines of 16 characters each //LiquidCrystal_PCF8574 lcd(0x27); // PCF8574 library variant void setup() { lcd.init(); // Initialize display lcd.backlight(); // connecting backlight lcd.setCursor(0,0); // Set the cursor to the beginning of the first line lcd.print("Hello"); // Typing text on the first line lcd.setCursor(0,1); // Setting the cursor to the beginning of the second line lcd.print("NerdyTechy"); // Typing on the second line } void loop() { }
Description of functions and methods of the LiquidCrystal_I2C library:
home()and
clear()– the first function lets you return the cursor to the beginning of the screen, the second one does the same, but it removes everything that was on the monitor before.
write(ch)– allows us to write a single character ch to the screen.
cursor()and
noCursor()– shows/hides the cursor on the screen.
blink()and
noBlink()– cursor blinks/unblinks (if on).
display()and
noDisplay()– allows to enable/disable display.
scrollDisplayLeft()and
scrollDisplayRight()– scrolls the screen one character to the left/right.
autoscroll()and
noAutoscroll()– allows to enable/disable autoscroll mode. In this mode, each new character is written in the same place, displacing previously written on the screen.
leftToRight()and
rightToLeft()– Sets the direction of the text to be displayed – from left to right or from right to left.
createChar(ch, bitmap)– creates a character with the code ch (0 – 7), using an array of bitmap bitmaps to create black and white dots.
Alternative Library for Working with I2C Display
In some cases, when using the above library with devices equipped with PCF8574 controllers, errors can occur. In that case, you can offer as an alternative to the library LiquidCrystal_PCF8574.h. It extends LiquidCrystal_I2C, so you shouldn’t have any problems using it.
Problems Connecting the I2C LCD
If you don’t get any writing on display after loading the sketch, try the following steps.
First, you can increase or decrease the contrast of the monitor. Often characters are just not visible due to the contrast mode and backlighting.
If this does not help, then check if the pins are connected correctly and if the backlight power is connected. If you used a separate I2C adapter, check the quality of the solder pins again.
Another common cause of missing text on the screen can be a wrong I2C address. Try changing the device address from 0x27 to 0x20 or to 0x3F. Different vendors may have different default addresses. If this does not help, you can run the I2C scanner sketch, which looks through all connected devices and detects their address by brute force.
If the screen still does not work, try to unsolder the adapter and connect the LCD normally.
Conclusion
This article covers the fundamental questions about using the LCD screen in complex Arduino projects when we need to save some of the available pins. A simple and inexpensive I2C adapter will allow you to connect a 1602 LCD screen taking up only two analog pins. In many situations, this can be very important. The price for convenience is the need to use an additional module – converter and library. In our opinion, it is not a high price for the convenience, and we highly recommend to use this feature in projects. | https://nerdytechy.com/arduino-lcd-i2c-tutorial/ | CC-MAIN-2021-31 | refinedweb | 1,728 | 63.9 |
how to could i get Multiple records from jsonobject.
json code is {"BrandNameid":"1","BrandNameid":"2", "BrandNameid":"3"}
i am unable to segregate BrandNameid for earch record.
Post your Comment
To Retrieve a Particular Object From an ArrayList
To Retrieve a Particular Object From an ArrayList
... objects. Now retrieve an object( that
is contained in the arraylist) using the get... an ArrayList object (that contains multiple elements) using the
get() method
Arraylist from row values
Arraylist from row values Hello,
can anyone please help on how to make an arraylist from the row values of a particular column from a database...;
class Retrieve{
public static void main(String[] args){
try
Retrieve all the students in the same year(Java ArrayList)?
Retrieve all the students in the same year(Java ArrayList)? FoundStudents.jsp
year- parameter I receive from a form
search- is an object of type... = search the ArrayList students starting from this index, not from the beginning
arraylist
arraylist Hi
How can we eliminet duplicate element from arraylist?
How can we find highest salary from arraylist ?
How can we highest key value pair from map?
Thanks
Kalins Naik
Remove duplicates from Arraylist
Cannot assign an ArrayList to an empty ArrayList
); This method returns an ArrayList of students that are in a particular year. I...Cannot assign an ArrayList to an empty ArrayList I have a java file, in which a method returns an ArrayList. This ArrayList is supposed to contain
How to use Arraylist object in .... struts 2? - Struts
object with that tag.
Im retrieving the values for arraylist object from...How to use Arraylist object in .... struts 2? Hi Members,
I saw... object should be identified by the tab, tag.
The item selected from first
ArrayList object
ArrayList object i have am ArrayList object it containg data base records in it,
now i want to display this ArrayList object data in my jsp programe,
plz help me
arraylist
arraylist Hi
how can we eliminet duplicate element from arraylist in java?
how can we achieve data abstrcation and encapulation in java?
how many... Duplicates from ArryaList
Encapsulation And Abstraction
Replace an object with set(int, Object) method
objects using the add(int,object) method.
Now replace an object from a particular... from a particular position specified by a index value.
Here is an example...
Replace an object with set(int, Object) method
arraylist
data into an arraylist and display the data of the particular employee according...arraylist Hi
i have class A , i have added employee name and id in arraylist, then how can i find out all infomation of class A using emplyee
bean object
bean object i have to retrieve data from the database and want... java.util.*;
public class Bean {
public List dataList(){
ArrayList list=new ArrayList();
try{
Class.forName("com.mysql.jdbc.Driver
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arrayList how do i print a single index have multiple values
String dist = "select distcode,distname from iwmpdistrict where stcode=29" ps = con.prepareStatement(dist
Remove duplicates from ArrayList
Remove duplicates from ArrayList
Sometimes we added large amount of data... the Set back to the ArrayList.
Here is the code:
import java.util.*;
public class RemoveDuplicate {
public static void removeDuplicates(ArrayList list
arraylist of an arraylist
arraylist of an arraylist Can anyone suggest me how to use arraylist of an arraylist?? how to put data into it and get data from it???? becoz i want to make rows and column dynamic which can grow as per requirement?????/ plz
how to retreive data from database of a particular user after login
how to retreive data from database of a particular user after login hi I m developing a project on hospital management and I m not able to retrieve... my question is how to retrieve this information of user after registration
Retrieve date from MYSQL database
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In this tutorial, you will learn how to retrieve date from database.
Storing and Retrieving dates from the database is a common task. MYSQL
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The session object is used by the developers to store and retrieve user's...(java.lang.String name) - for retrieving the object from the session object.
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maximum size of arraylist - java
an element from the middle of the array list are not efficient since the arraylist...maximum size of arraylist - java 1.what is the maximum size of arraylist?
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object array
(object{[] obj) {}
Now my question is what is the string length and how to retrieve element from vector and if i give key then i will get the value.
2) from...object array Hi
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Collection : ArrayList Example
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add(Object o) - It adds the specified element at
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Example :
package...(list.get(i));
}
// Removing element from ArrayList
list.remove(3);
size
How to read and retrieve jtable row values into jtextfield on clicking at particular row ...
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I am developing a desktop... to read all the values of particular row at which mouse is clicked. and display
Find max and min value from Arraylist
Find max and min value from Arraylist
In this tutorial, you will learn how to find the maximum and minimum value
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how to retrieve data from table with runtime values in sql?
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For example,
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I know how to retrieve a particular
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FATCH MULTIPLE RECORDS FROM JSONCODE IN J2MEPARVEEN SAINI April 2, 2012 at 11:30 AM
how to could i get Multiple records from jsonobject. json code is {"BrandNameid":"1","BrandNameid":"2", "BrandNameid":"3"} i am unable to segregate BrandNameid for earch record.
Post your Comment | http://www.roseindia.net/discussion/20104-To-Retrieve-a-Particular-Object-From-an-ArrayList.html | CC-MAIN-2015-32 | refinedweb | 1,190 | 55.24 |
A cryptic yet true answer to the question “Why should I test?” is “because you are human.” Because humans make mistakes, having a tool to inform them when they make one is helpful, isn’t it? In this article based on chapter 2 of Rails 3 in Action, the authors show you how to save your bacon with test-driven development.
You may also be interested in…
A cryptic yet true answer to the question "Why should I test?"
is "because you are human." Humans—the large majority of this book’s
audience—make mistakes. It’s one of our favorite ways to learn. Because humans
make mistakes, having a tool to inform them when they make one is helpful,
isn’t it? Automated testing provides a quick safety net to inform developers
when they make mistakes. By they, of course, we mean you.
We want you to make as few mistakes as possible. We want you to
save your bacon! TDD and BDD also give you time to think through your decisions
before you write any code. By first writing the test for the implementation,
you are (or, at least, you should be) thinking through the implementation: the
code you’ll write after the test and how you’ll make
the test passes. If you find the test difficult to write, then perhaps the
implementation could be improved. Unfortunately, there’s no clear way to
quantify the difficulty of writing a test and working through it other than to
consult with other people who are familiar with the process.
Once the test is implemented, you should go about writing some
code that your test can pass. If you find yourself working backward—rewriting
your test to fit a buggy implementation—it’s generally best to rethink the test
and scrap the implementation. Test first, code later.
Automated testing is much, much easier than manual testing. Have
you ever gone through a website and manually filled in a form with specific
values to make sure it conforms to your expectations? Wouldn’t it be faster and
easier to have the computer do this work? Yes, it would, and that’s the beauty
of automated testing: you won’t spend your time manually testing your code
because you’ll have written test code to do that for you.
On the off chance you break something, the tests are there to
tell you the what, when, how, and why of the breakage. Although tests can never
be 100% guaranteed, your chances of getting this information without first
having written tests are 0%. Nothing is worse than finding out something is
broken through an early-morning phone call from an angry customer. Tests work
toward preventing such scenarios by giving you and your client peace of mind.
If the tests aren’t broken, chances are high (though not guaranteed) that the
implementation isn’t either.
You’ll likely at some point face a situation in which something
in your application breaks when a user attempts to perform an action you didn’t
consider in your tests. With a base of tests, you can easily duplicate the
scenario in which the user encountered the breakage, generate your own failed
test, and use this information to fix the bug. This commonly used practice is
called regression testing.
It’s valuable to have a solid base of tests in the application so
you can spend time developing new features properly rather
than fixing the old ones you didn’t do quite right. An application without
tests is most likely broken in one way or another.
The first testing library for Ruby was Test::Unit, which was
written by Nathaniel Talbott back in 2000 and is now part of the Ruby core
library. The documentation for this library gives a fantastic overview of its
purpose, as summarized by the man himself:.
—Nathaniel Talbott
The UI Talbott references could be a
terminal, a web page, or even a light.[1]
A common practice you’ll hopefully by now have experienced in the
Ruby world is to let the libraries do a lot of the hard work for you. Sure, you
could write a file yourself that loads one of your
other files and runs a method and makes sure it works, but why do that when
Test::Unit already provides that functionality for such little cost? Never reinvent
the wheel when somebody’s done it for you.
Test::Unit
Now you’re going to write a test, and you’ll write the code for
it later. Welcome to TDD.
To try out Test::Unit, first create a new directory called example
and in that directory make a file called example_test.rb. It’s good practice to
suffix your filenames with _test
so it’s obvious from the filename that it’s a test file. In this
file, you’re going to define the most basic test possible, as shown in the
following listing.
_test
require 'test/unit'
class ExampleTest < Test::Unit::TestCase
def test_truth
assert true
end
end
To make this a Test::Unit test, you begin by requiring test/unit, which
is part of Ruby’s standard library. This provides the Test::Unit::TestCase class inherited from
on the next line. Inheriting from this class provides the functionality to run
any method defined in this class whose name begins with test. Additionally, you can define tests
by using the test method:
Test::Unit::TestCase
test "truth" do
assert true
end
To run this file, you run ruby example_test.rb in the terminal.
When this command completes, you see some output, the most relevant being two
of the lines in the middle:
.
1 tests, 1 assertions, 0 failures, 0 errors, 0 skips
The first line is a singular period. This is Test::Unit’s way of
indicating that it ran a test and the test passed. If the test had failed, it
would show up as an F; if it had errored, an E. The second line provides statistics on
what happened, specifically that there was one test and one assertion, and that
nothing failed, there were no errors, and nothing was skipped. Great success!
The assert method
in your test makes an assertion that the argument passed to it evaluates to true. This test
passes given anything that’s not nil or false.
When this method fails, it fails the test and raises an exception. Go ahead,
try putting 1 there
instead of true. It still works:
In the following listing, you remove the test_ from the beginning of your method and
define it as simply a truth
method.
test_
def truth
assert true
end
Test::Unit tells you there were no tests specified by running
the default_test
method internal to Test::Unit:
default_test
No tests were specified.
1 tests, 1 assertions, 1 failures, 0 errors
Remember to always prefix Test::Unit methods with test!
Let’s make this a little more complex by creating a
bacon_test.rb file and writing the test shown in the following listing.
require 'test/unit'
class BaconTest < Test::Unit::TestCase
def test_saved
assert Bacon.saved?
end
end
Of course, you want to ensure that your bacon[2] is always saved, and this is how you
do it. If you now run the command to run this file, ruby bacon_test.rb, you get an error:
NameError: uninitialized constant BaconTest::Bacon
Your test is looking for a constant called Bacon and cannot find
it because you haven’t yet defined the constant. For this test, the constant
you want to define is a Bacon class.
Bacon
You can define this new class before or after the test. Note that
in Ruby you usually must define constants and variables before you use them. In
Test::Unit tests, the code is only run when it finishes evaluating it, which
means you can define the Bacon class after the test. In the next listing, you
follow the more conventional method of defining the class above the test.
require 'test/unit'
class Bacon
end
class BaconTest < Test::Unit::TestCase
def test_saved
assert Bacon.saved?
end
end
Upon rerunning the test, you get a different error:
NoMethodError: undefined method `saved?' for Bacon:Class
Progress! It recognizes there’s now a Bacon class, but there’s no saved? method for this
class, so you must define one, as in the following listing.
class Bacon
def self.saved?
true
end
end
One more run of ruby bacon_test.rb and you can see that the test is now passing:
Your bacon is indeed saved! Now any time that you want to check
if it’s saved, you can run this file. If somebody else comes along and changes
that true value
to a false, then
the test will fail:
F
1) Failure:
test_saved(BaconTest) [bacon_test.rb:11]:
Failed assertion, no message given.
Test::Unit reports "Failed assertion, no message given" when an
assertion fails. You should probably make that error message clearer! To do so,
you can specify an additional argument to the assert method in
your test, like this:
assert Bacon.saved?, "Our bacon was not saved :("
Now when you run the test, you get a clearer error message:
1) Failure:
test_saved(BaconTest) [bacon_test.rb:11]:
Our bacon was not saved :(
You’ve just seen the basics of TDD using Test::Unit. It’s handy
to know because it establishes the basis for TDD in Ruby. Test::Unit is also
the default testing framework for Rails, so you may see it around in your
travels.
Here are some other Manning titles you
might be interested in:
Grails in Action
Glen Smith and Peter Ledbrook
Griffon in Action
Andres Almiray and Danno Ferrin
Spring in Action, Third Edition
Craig Walls
[1] Such as
the one GitHub has made:.
[2] Both the metaphorical and the crispy. | http://www.codeproject.com/Articles/260459/Rails-3-in-Action-Test-Driven-Development?PageFlow=FixedWidth | CC-MAIN-2016-36 | refinedweb | 1,634 | 71.55 |
This channel is now CLOSED. Please use gitter.im/scala/scala for user questions and gitter.im/scala/contributors for compiler development.?
Selectablenow?
Gitven the following code:
object ExtractSome { def unapply[A](s: Some[A]): Option[A] = s } def unwrap(oi: Option[Int]): Int = oi match { case ExtractSome(i) => i }
I get the following warning:
: _: Option[Int]
Option[Int], it specifically fails on
None
ExtractSome.unapplyto
Some[A], I do get the warning I'd expect:
: None
Some, even if it returns a
Some?
If I change my
unapply to:
def unapply[A](o: Option[A]): Some[A] = o match { case s: Some[A] => s case _ => sys.error("fail") }
I don't get a warning. I understand that as far as the types are concerned, this makes sense, but how does the compiler know without special handling of
Some?
Two
Option-less pattern matching | https://gitter.im/lampepfl/dotty?at=5cd565bada34620ff919643e | CC-MAIN-2021-49 | refinedweb | 146 | 59.4 |
- A First Technique for Blending Images
- A Better Technique for Blending Images
- Blending Slides
- Conclusion
Many slideshow programs provide visual transitions between consecutively displayed images. The same is true of movies, which often provide visual transitions between consecutive scenes (sequences of images). One of these transitions is the blending transition, which gradually combines the next image or scene with the current image/scene, until the next image or scene completely replaces the current image/scene.
This article introduces you to the blending transition. First we'll look at an algorithm for blending two images by directly manipulating their pixels, followed by a Java application that demonstrates this algorithm. Then we'll focus on a superior technique for blending images: alpha compositing. Finally, I'll reveal a Java slideshow application that performs slide transitions via blending as a practical demonstration.
A First Technique for Blending Images
You can blend two images of the same size into a resulting image by linearly combining their pixel values. The idea is to take a weighted average of equivalent pixel values, such as 50% of the first image's pixel values and 50% of the second image's pixel values (which yields a resulting image that equally reveals both images). The algorithm described in Listing 1 demonstrates this blending technique.
Listing 1 Blending algorithm.
Assume images X and Y with the same widths and the same heights. Assume X and Y store their pixels in the RGB format. Assume image Z holds the blended image with the same width, height, and RGB format. SET weight TO 0.3 // Percentage fraction (between 0 and 1) of image X to retain // (retain 30%). The percentage fraction of image Y to retain is // set to 1-weight so that each color component remains in range // 0-255. FOR row = 1 TO height FOR col = 1 TO width SET Z [row][col].red TO X [row][col].red*weight+Y [row][col].red*(1-weight) SET Z [row][col].green TO X [row][col].green*weight+Y [row][col].green*(1-weight) SET Z [row][col].blue TO X [row][col].blue*weight+Y [row][col].blue*(1-weight) END FOR END FOR
The Blender1 application in Listing 2 demonstrates this algorithm. Blender1 creates a GUI with an image panel and a slider, loads two JPEG images from files image1.jpg and image2.jpg, and displays the first image. The application responds to slider movements by blending these images and displaying the blended result.
Listing 2 Blender1.java.
// Blender1.java import java.awt.*; import java.awt.image.*; import javax.swing.*; import javax.swing.event.*; /** * This class describes and contains the entry point to an application that * demonstrates the blending transition. */ public class Blender1 extends JFrame { /** * Construct Blender1 GUI. */ public Blender1 () { super ("Blender #1"); setDefaultCloseOperation (EXIT_ON_CLOSE); // Load first image from JAR file and draw image into a buffered image. ImageIcon ii1 = new ImageIcon (getClass ().getResource ("/image1.jpg")); final BufferedImage bi1; bi1 = new BufferedImage (ii1.getIconWidth (), ii1.getIconHeight (), BufferedImage.TYPE_INT_RGB); Graphics2D g2d = bi1.createGraphics (); g2d.drawImage (ii1.getImage (), 0, 0, null); g2d.dispose (); // Load second image from JAR file and draw image into a buffered image. ImageIcon ii2 = new ImageIcon (getClass ().getResource ("/image2.jpg")); final BufferedImage bi2; bi2 = new BufferedImage (ii2.getIconWidth (), ii2.getIconHeight (), BufferedImage.TYPE_INT_RGB); g2d = bi2.createGraphics (); g2d.drawImage (ii2.getImage (), 0, 0, null); g2d.dispose (); // Create an image panel capable of displaying entire image. The widths // of both images and the heights of both images must be identical. final ImagePanel ip = new ImagePanel (); ip.setPreferredSize (new Dimension (ii1.getIconWidth (), ii1.getIconHeight ())); getContentPane ().add (ip, BorderLayout.NORTH); // Create a slider for selecting the blending percentage: 100% means // show all of first image; 0% means show all of second image. final JSlider slider = new JSlider (JSlider.HORIZONTAL, 0, 100, 100); slider.setMinorTickSpacing (5); slider.setMajorTickSpacing (10); slider.setPaintTicks (true); slider.setPaintLabels (true); slider.setLabelTable (slider.createStandardLabels (10)); slider.setInverted (true); ChangeListener cl; cl = new ChangeListener () { public void stateChanged (ChangeEvent e) { // Each time the user adjusts the slider, obtain the new // blend percentage value and use it to blend the images. int value = slider.getValue (); ip.setImage (blend (bi1, bi2, value/100.0)); } }; slider.addChangeListener (cl); getContentPane ().add (slider, BorderLayout.SOUTH); // Display the first image, which corresponds to a 100% blend percentage. ip.setImage (bi1); pack (); setVisible (true); } /** * Blend the contents of two BufferedImages according to a specified * weight. * * @param bi1 first BufferedImage * @param bi2 second BufferedImage * @param weight the fractional percentage of the first image to keep * * @return new BufferedImage containing blended contents of BufferedImage * arguments */ public BufferedImage blend (BufferedImage bi1, BufferedImage bi2, double weight) { if (bi1 == null) throw new NullPointerException ("bi1 is null"); if (bi2 == null) throw new NullPointerException ("bi2 is null"); int width = bi1.getWidth (); if (width != bi2.getWidth ()) throw new IllegalArgumentException ("widths not equal"); int height = bi1.getHeight (); if (height != bi2.getHeight ()) throw new IllegalArgumentException ("heights not equal"); BufferedImage bi3 = new BufferedImage (width, height, BufferedImage.TYPE_INT_RGB); int [] rgbim1 = new int [width]; int [] rgbim2 = new int [width]; int [] rgbim3 = new int [width]; for (int row = 0; row < height; row++) { bi1.getRGB (0, row, width, 1, rgbim1, 0, width); bi2.getRGB (0, row, width, 1, rgbim2, 0, width); for (int col = 0; col < width; col++) { int rgb1 = rgbim1 [col]; int r1 = (rgb1 >> 16) & 255; int g1 = (rgb1 >> 8) & 255; int b1 = rgb1 & 255; int rgb2 = rgbim2 [col]; int r2 = (rgb2 >> 16) & 255; int g2 = (rgb2 >> 8) & 255; int b2 = rgb2 & 255; int r3 = (int) (r1*weight+r2*(1.0-weight)); int g3 = (int) (g1*weight+g2*(1.0-weight)); int b3 = (int) (b1*weight+b2*(1.0-weight)); rgbim3 [col] = (r3 << 16) | (g3 << 8) | b3; } bi3.setRGB (0, row, width, 1, rgbim3, 0, width); } return bi3; } /** * Application entry point. * * @param args array of command-line arguments */ public static void main (String [] args) { Runnable r = new Runnable () { public void run () { // Create Blender1's GUI on the event-dispatching // thread. new Blender1 (); } }; EventQueue.invokeLater (r); } } /** * This class describes a panel that displays a BufferedImage's contents. */ class ImagePanel extends JPanel { private BufferedImage bi; /** * Specify and paint a new BufferedImage. * * @param bi BufferedImage whose contents are to be painted */ void setImage (BufferedImage bi) { this.bi = bi; repaint (); } /** * Paint the image panel. * * @param g graphics context used to paint the contents of the current * BufferedImage */ public void paintComponent (Graphics g) { if (bi != null) { Graphics2D g2d = (Graphics2D) g; g2d.drawImage (bi, null, 0, 0); } } }
Blender1 uses the javax.swing.ImageIcon class with Class's public URL getResource(String name) method (in case the images are stored in a JAR file) to load both images. Because ImageIcon returns a java.awt.Image, and because blending needs pixel access, the image is copied to a java.awt.image.BufferedImage, which makes pixel access possible.
After performing sanity checks to ensure that its BufferedImage arguments are non-null, and that they have the same widths and heights, the public BufferedImage blend(BufferedImage bi1, BufferedImage bi2, double weight) method executes the blending algorithm. The weight value specifies the fractional percentage of the first image's pixel values to keep—from 1.0 (everything) to 0.0 (nothing).
To play with Blender1, first compile its source code (via javac Blender1.java) and run the application (via java Blender1). As you move the GUI's slider, the resulting change events convert the slider's percentage value to a fractional percentage weight, perform the blending, and update the image panel with the resulting image. Figure 1 shows the Blender1 GUI on a Windows XP platform. | http://www.informit.com/articles/article.aspx?p=1245201&seqNum=3 | CC-MAIN-2019-09 | refinedweb | 1,244 | 59.5 |
Using SD Card for the Whole Project.
Hi,
I am trying to implement a machine learning method on Pysense + LopY combo. I need to use Python libraries(e.g. Numpy, Scikit) that uses more a space than the flash memory, so I want to utilize SD card for that. I have several question that might help to achieve my task:
- Can I use SD card as to manage the whole project? Currently upload & download via REPL is only using flash memory. I created a data.txt but I am not able to fetch it via REPL. Is there any ways to achieve these?
- Can I create a lib folder (to upload python ML libraries) in SD card and use that instead of the lib folder that we upload to flash? Just achieving this might be adequate in my case.
Note: The ML method is Isolation Forest. You are not actually training anything, so the TinyML is out of question, hence I just need more space to implement that.
Cheers,
@hakan-kayan An example of a copy function:
import os def cp(s, t): try: if os.stat(t)[0] & 0x4000: # is directory t = t.rstrip("/") + "/" + s except OSError: pass with open(s, "rb") as s: with open(t, "wb") as t: while True: l = s.read(512) if not l: break t.write(l)
So can call that with:
from cp import cp
cp("source_name", "target_name")
if target_name is a directory, the target name will be create as target_name/source_name. So you could use:
cp("source_file", "/sd")
If you want to copy more than one file at once, you have to create a loop.
Hi Robert, could you provide an example please?
@Matthew-Felgate-0 said in Using SD Card for the Whole Project.:
os.rename('test.py','sd/test.py')
Sorry no, that is not possible. You cannot move files between volumes by renaming. You have to copy them.
@Matthew-Felgate-0
Thanks Mathew, I don't know how I missed
print(os.listdir('/sd'))to be honest. I need some fresh air I guess.
Regarding implementing Isolation Forest, for now it does not seem possible, as the library itself uses huge modules like Numpy. The discussion here also claims that is not possible import libraries like Numpy.
I will be looking for a workaround, even though I am not very hopeful.
- Matthew Felgate 0 Global Moderator last edited by Matthew Felgate 0
@hakan-kayan
Hi Hakan
In code, for example
main.pyyou would have to wrap it in a print statement:
print(os.listdir('/sd'))
Let me know if this works.
Writing files to SD card you can do manually by putting the SD card in your computer.
You could upload files to the board, then use REPL to move them to the SD card with the rename command:
os.rename('test.py','sd/test.py')
Matt
Update: I have tried with 32 GB SD card, the issue persists. The commands from main.py is ignored, but via REPL, they are working.
- hakan kayan last edited by hakan kayan
Hi @livius. Thanks for quick answer.
So I used the example given in Pycom documents and created text.txt file in the sd card.
from machine import SD import os import sys #sd = SD() #os.mount(sd, '/sd') # check the content os.listdir('/sd')
I commented os.mount() because it is already mounted. When I run this main.py file via REPL, it does not show anything. However running
os.listdir('/sd')from REPL console it outputs 'test.txt'.
The firmware version is 1.20.2.r4. The SD card is 64 GB, FAT32. The document says it supports up to 32 GB, that might be the issue?
Also regarding your answer, my guess is I should manually upload those libraries to SD card. There is no way to install via REPL.
@hakan-kayan
Yes, you can import modules from sd card.
first mount sd card
from machine import SD import os import sys sd = SD() os.mount(sd, '/sd')
now you must add sd card to search path
sys.path.append('/sd')
and you are ready to import any module from it e.g.: your module is placed in sd card and its name is
mysdcardfile.pythen you can import it like this
import mysdcardfile | https://forum.pycom.io/topic/6920/using-sd-card-for-the-whole-project | CC-MAIN-2022-33 | refinedweb | 717 | 77.53 |
DGL at a Glance¶
Author: Minjie Wang, Quan Gan, Jake Zhao, Zheng Zhang
DGL is a Python package dedicated to deep learning on graphs, built atop existing tensor DL frameworks (e.g. Pytorch, MXNet) and simplifying the implementation of graph-based neural networks.
The goal of this tutorial:
- Understand how DGL enables computation on graph from a high level.
- Train a simple graph neural network in DGL to classify nodes in a graph.
At the end of this tutorial, we hope you get a brief feeling of how DGL works.
This tutorial assumes basic familiarity with pytorch.
Tutorial problem description¶
The tutorial is based on the “Zachary’s karate club” problem. The karate club is a social network that includes 34 members and documents pairwise links between members who interact outside the club. The club later divides into two communities led by the instructor (node 0) and the club president (node 33). The network is visualized as follows with the color indicating the community:
The task is to predict which side (0 or 33) each member tends to join given the social network itself.
Step 1: Creating a graph in DGL¶
Create the graph for Zachary’s karate club as follows:
import dgl import numpy as np def build_karate_club_graph(): # All 78 edges are stored in two numpy arrays. One for source endpoints # while the other for destination endpoints. src = np.array([1, 2, 2, 3, 3, 3, 4, 5, 6, 6, 6, 7, 7, 7, 7, 8, 8, 9, 10, 10, 10, 11, 12, 12, 13, 13, 13, 13, 16, 16, 17, 17, 19, 19, 21, 21, 25, 25, 27, 27, 27, 28, 29, 29, 30, 30, 31, 31, 31, 31, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33]) dst = np.array([0, 0, 1, 0, 1, 2, 0, 0, 0, 4, 5, 0, 1, 2, 3, 0, 2, 2, 0, 4, 5, 0, 0, 3, 0, 1, 2, 3, 5, 6, 0, 1, 0, 1, 0, 1, 23, 24, 2, 23, 24, 2, 23, 26, 1, 8, 0, 24, 25, 28, 2, 8, 14, 15, 18, 20, 22, 23, 29, 30, 31, 8, 9, 13, 14, 15, 18, 19, 20, 22, 23, 26, 27, 28, 29, 30, 31, 32]) # Edges are directional in DGL; Make them bi-directional. u = np.concatenate([src, dst]) v = np.concatenate([dst, src]) # Construct a DGLGraph return dgl.DGLGraph((u, v))
Print out the number of nodes and edges in our newly constructed graph:
G = build_karate_club_graph() print('We have %d nodes.' % G.number_of_nodes()) print('We have %d edges.' % G.number_of_edges())
Out:
We have 34 nodes. We have 156 edges.
Visualize the graph by converting it to a networkx graph:
import networkx as nx # Since the actual graph is undirected, we convert it for visualization # purpose. nx_G = G.to_networkx().to_undirected() # Kamada-Kawaii layout usually looks pretty for arbitrary graphs pos = nx.kamada_kawai_layout(nx_G) nx.draw(nx_G, pos, with_labels=True, node_color=[[.7, .7, .7]])
Step 2: Assign features to nodes or edges¶
Graph neural networks associate features with nodes and edges for training. For our classification example, since there is no input feature, we assign each node with a learnable embedding vector.
# In DGL, you can add features for all nodes at once, using a feature tensor that # batches node features along the first dimension. The code below adds the learnable # embeddings for all nodes: import torch import torch.nn as nn import torch.nn.functional as F embed = nn.Embedding(34, 5) # 34 nodes with embedding dim equal to 5 G.ndata['feat'] = embed.weight
Print out the node features to verify:
# print out node 2's input feature print(G.ndata['feat'][2]) # print out node 10 and 11's input features print(G.ndata['feat'][[10, 11]])
Out:
tensor([-2.4510, -0.6563, -0.7395, 1.6401, 2.2282], grad_fn=<SelectBackward>) tensor([[-1.6371, 0.1195, -0.5801, 0.6771, -1.2104], [-0.0391, -0.2906, -0.7418, -0.0126, -0.3276]], grad_fn=<IndexBackward>)
Step 3: Define a Graph Convolutional Network (GCN)¶
To perform node classification, use the Graph Convolutional Network (GCN) developed by Kipf and Welling. Here is the simplest definition of a GCN framework. We recommend that you read the original paper for more details.
- At layer \(l\), each node \(v_i^l\) carries a feature vector \(h_i^l\).
- Each layer of the GCN tries to aggregate the features from \(u_i^{l}\) where \(u_i\)‘s are neighborhood nodes to \(v\) into the next layer representation at \(v_i^{l+1}\). This is followed by an affine transformation with some non-linearity.
The above definition of GCN fits into a message-passing paradigm: Each node will update its own feature with information sent from neighboring nodes. A graphical demonstration is displayed below.
In DGL, we provide implementations of popular Graph Neural Network layers under
the dgl.<backend>.nn subpackage. The
GraphConv module
implements one Graph Convolutional layer.
from dgl.nn.pytorch import GraphConv
Define a deeper GCN model that contains two GCN layers:
class GCN(nn.Module): def __init__(self, in_feats, hidden_size, num_classes): super(GCN, self).__init__() self.conv1 = GraphConv(in_feats, hidden_size) self.conv2 = GraphConv(hidden_size, num_classes) def forward(self, g, inputs): h = self.conv1(g, inputs) h = torch.relu(h) h = self.conv2(g, h) return h # The first layer transforms input features of size of 5 to a hidden size of 5. # The second layer transforms the hidden layer and produces output features of # size 2, corresponding to the two groups of the karate club. net = GCN(5, 5, 2)
Step 4: Data preparation and initialization¶
We use learnable embeddings to initialize the node features. Since this is a semi-supervised setting, only the instructor (node 0) and the club president (node 33) are assigned labels. The implementation is available as follow.
inputs = embed.weight labeled_nodes = torch.tensor([0, 33]) # only the instructor and the president nodes are labeled labels = torch.tensor([0, 1]) # their labels are different
Step 5: Train then visualize¶
The training loop is exactly the same as other PyTorch models. We (1) create an optimizer, (2) feed the inputs to the model, (3) calculate the loss and (4) use autograd to optimize the model.
import itertools optimizer = torch.optim.Adam(itertools.chain(net.parameters(), embed.parameters()), lr=0.01) all_logits = [] for epoch in range(50): logits = net(G, inputs) # we save the logits for visualization later all_logits.append(logits.detach()) logp = F.log_softmax(logits, 1) # we only compute loss for labeled nodes loss = F.nll_loss(logp[labeled_nodes], labels) optimizer.zero_grad() loss.backward() optimizer.step() print('Epoch %d | Loss: %.4f' % (epoch, loss.item()))
Out:
Epoch 0 | Loss: 0.5709 Epoch 1 | Loss: 0.5381 Epoch 2 | Loss: 0.5062 Epoch 3 | Loss: 0.4742 Epoch 4 | Loss: 0.4429 Epoch 5 | Loss: 0.4122 Epoch 6 | Loss: 0.3817 Epoch 7 | Loss: 0.3518 Epoch 8 | Loss: 0.3218 Epoch 9 | Loss: 0.2928 Epoch 10 | Loss: 0.2650 Epoch 11 | Loss: 0.2386 Epoch 12 | Loss: 0.2138 Epoch 13 | Loss: 0.1909 Epoch 14 | Loss: 0.1696 Epoch 15 | Loss: 0.1502 Epoch 16 | Loss: 0.1324 Epoch 17 | Loss: 0.1163 Epoch 18 | Loss: 0.1019 Epoch 19 | Loss: 0.0892 Epoch 20 | Loss: 0.0780 Epoch 21 | Loss: 0.0681 Epoch 22 | Loss: 0.0595 Epoch 23 | Loss: 0.0520 Epoch 24 | Loss: 0.0455 Epoch 25 | Loss: 0.0399 Epoch 26 | Loss: 0.0350 Epoch 27 | Loss: 0.0308 Epoch 28 | Loss: 0.0272 Epoch 29 | Loss: 0.0241 Epoch 30 | Loss: 0.0214 Epoch 31 | Loss: 0.0190 Epoch 32 | Loss: 0.0170 Epoch 33 | Loss: 0.0153 Epoch 34 | Loss: 0.0137 Epoch 35 | Loss: 0.0124 Epoch 36 | Loss: 0.0112 Epoch 37 | Loss: 0.0102 Epoch 38 | Loss: 0.0094 Epoch 39 | Loss: 0.0086 Epoch 40 | Loss: 0.0079 Epoch 41 | Loss: 0.0073 Epoch 42 | Loss: 0.0068 Epoch 43 | Loss: 0.0063 Epoch 44 | Loss: 0.0059 Epoch 45 | Loss: 0.0055 Epoch 46 | Loss: 0.0052 Epoch 47 | Loss: 0.0049 Epoch 48 | Loss: 0.0046 Epoch 49 | Loss: 0.0044
This is a rather toy example, so it does not even have a validation or test set. Instead, Since the model produces an output feature of size 2 for each node, we can visualize by plotting the output feature in a 2D space. The following code animates the training process from initial guess (where the nodes are not classified correctly at all) to the end (where the nodes are linearly separable).
import matplotlib.animation as animation import matplotlib.pyplot as plt def draw(i): cls1color = '#00FFFF' cls2color = '#FF00FF' pos = {} colors = [] for v in range(34): pos[v] = all_logits[i][v].numpy() cls = pos[v].argmax() colors.append(cls1color if cls else cls2color) ax.cla() ax.axis('off') ax.set_title('Epoch: %d' % i) nx.draw_networkx(nx_G.to_undirected(), pos, node_color=colors, with_labels=True, node_size=300, ax=ax) fig = plt.figure(dpi=150) fig.clf() ax = fig.subplots() draw(0) # draw the prediction of the first epoch plt.close()
The following animation shows how the model correctly predicts the community after a series of training epochs.
ani = animation.FuncAnimation(fig, draw, frames=len(all_logits), interval=200)
Next steps¶
In the next tutorial, we will go through some more basics of DGL, such as reading and writing node/edge features.
Total running time of the script: ( 0 minutes 0.565 seconds)
Gallery generated by Sphinx-Gallery | https://docs.dgl.ai/tutorials/basics/1_first.html | CC-MAIN-2020-29 | refinedweb | 1,587 | 69.28 |
This document is intended to help you understand how the various components of TurboGears 2 work together, and what happens to a web-request on the way into your controller code.
It may seem like there are a lot of layers here, and there are, but most of the time you don’t need to know anything about how they work, just that they are there to do work for you.
The first thing that happens is that some WSGI (web server gateway interface) compliant HTTP server recieves an HTTP message from somebody, and it calls your TG application which is a WSGI app.
For those new to WSGI, it’s a very simple interface that defines how web servers interact with python methods or functions, or really any callable.
The basic WSGI interface is this:
def simple_app(environ, start_response): """Simplest possible application object""" status = '200 OK' response_headers = [('Content-type','text/plain')] start_response(status, response_headers) return ['Hello world!\n']
Fundamentally, WSGI means your python function gets called with two things, an environ dictionary, and a start_response callable. Before your function returns, you have to pass a status, and a set of headers to the start_response method, and then you’re free to return a list (or any itterable) of strings as the response body.
The environ dictionary, is a copy of the CGI spec’s ENVIRON (). And it has everything you need to know about the incoming request.
One more thing to know about WSGI is that it’s easy for a python function or method to take and environ and start_response to do some stuff, and then to call another function that’s also a WSGI app (meaning it takes an environ and a start response). When an application like this sits between the “real” webserver and another WSGI app, we call it middleware.
The TurboGears request/response cycle is composed of various bits of middleware that help make writing web applicaitons easier for you.
Here’s a quick outline of the stack, but we’ll be going through the pieces in a bit more detail as we go.
WSGI Server PasteCascade - serves one of a list of WSGI apps. StaticFile Server - serves static files from /public OR TurboGears Application: - the TG stack Registry Manager - sets up the request proxy, etc. Error Middleware - if the path goes to _debug handle the request Database Session Manager - setup the DBSession Transaction Manager - Authentication - add info to the environ if user is authenticated Authorization - add more info to the environ for authorization. ToscaWidgets - nothing on the way in. Cache - sets up the cache Session - sets up the web session Routes - parses the URL and adds info to environ Custom Middleware - User defined middleware TurboGearsApp -- calls WSGI style controller ObjectDispatchController -- gets params, do validation, etc Your Controller Code -- does anything! ObjectDispatchController -- renders response, etc. ToscaWidgets - injects resources used by widgets Transaction Manager - commits or rolls back transaction Database Session Manager - cleans up the DBSession Error Middleware - displays error pages, etc
In total, this stack provides automatic database helpers, sessions, authentication, authorization, caching, sessions, URL based dispatch, and injection of CSS and JS resources into your app as required, and generally makes web development easier.
WSGI Server PasteCascade - Tries one app then the next StaticFile Server OR TurboGears Application Stack
The first thing that gets called by the WSGI server on the way into the TG stack is the PasteCascade. Paste’s Cascade app tries several WSGI apps in order, if the first app returns an HTTP Not Found (404) status code, it moves on to the second, and so on. In the default TG configuration the Cascade does two things 1) tries the StaticFile Server which serves up static files from your public directory, 2) tries the main TurboGears application.
Registry Manager - sets up the request proxy, etc. Error Middleware - if the path goes to _debug handle the request. {{ lots of stuff }} Error Middlware - redirect to nice pages on HTTP error codes, and produce debug pages/email for python errors.
The next thing on the stack is the Registry Manager which sets up some global objects that proxy to the current thread, and the current request. This is what allows you to do from tg import request and then use that to manipulate just the current request. It also has a less-often used but still useful feature which allows you to put one TurboGears application inside of another, and still have different config objects, etc. If you hear anybody talking about “Stacked Object Proxies” or SOP’s that’s what this is.
The next layer on the stack is the error handling middleware. This is there to provide debugging helpers when python exceptions or other application errors happen. In debug mode this provides you with the nice interactive debugger, and in production mode it’s what logs errors and sends out e-mails about the failures. Whenever a request comes in that lives on the _debug path, the error handler middleware looks up the info and responds directly.
Other than that error handling middleware doesn’t do much on the way in to the stack, but on the way out it catches errors saves data, and does the right thing when _debug requests come in for that info.
Inside the error handler, the next thing we setup is a couple of database helpers:
Database Session Manager - creates a DBSession for the request Transaction Manager - regesters a TransactionManager for the request. {{ lots of stuff }} Transaction Manager - Commit the transaction Database Session Manager - Clear the DBSession.
Inside the error handling middleware is a tiny little piece of middleware that sets up a SQLAlchemy database session for this request on the way in, and clears it out on the way out of the stack. This means that in TG2 by default you get a new DBSession for every request, and everything is cleared away when you’re done with it. This keeps requests isolated, and matches the “stateless” pattern of HTTP.
And inside that is the middleware portion of the automatic transaction system. When a request has updated the DBSession in any way (the in memory copies of database data) a transaction is automatically registered, and the Transaction Manager will handle it. If a python exception happens, an HTTP Error Code is returned,or transaction.doom() is called during the request, the transaction will be rolled back on the way out.
There’s a lot more to the transaction manager than just that, because you can setup new TransactionManager classes for whatever you want. You can write an e-mail module that does not send e-mail until the database transaction is committed. And if you have a database that supports two-phase commits you can write transactions that span multiple data sources.
ToscaWidgets - nothing much on the way in. {{ lots of stuff }} ToscaWidgets - inject resources into the generated
Nothing much on the way in. Inject JS, and CSS resources used by widgets in the main app.
Cache - sets up the cache Session - sets up the web session Routes - parses the URL and adds info to environ
The middleware outside of Core Middleware is optional and can often be configured out via special config values in app_cfg.py, and can be manipulated in any way you can imagine by subclassing AppConfig and replacing the methods that set it up. TurboGears itself has code that requires that the core middleware be in place, so you won’t want to mess with this stuff without a good reason. This is particularly true of Routes which can only be configured out of your app if you reimplement TGApp. Please see App Config General Options for more information on how to modify the core middleware.
The Cache middleware sets up a reference to the threadlocal cache manager that turbogears uses to interface to whatever backend you’re using for caching. The cache manager is injected into the environ so that it’s available to anything that happens in the request. In the future it’s possible that this will no longer be middleware, and will simply become another global object that is configured separately from the WSGI stack.
The Session middleware also sets up a reference to a threadlocal session manager, and at the moment both Session and Cache use the same back-ends based on Beaker.
Finally the Routes middleware inspects the URL of the request, and tries to map it to a series of “routes” which explain what controller and controller method should be called to handle that request. The Routes middleware then puts this information into the controller so that the TGApp can call the right method.
By default TG is setup with one route, that goes to the “routes_placeholder” method on your RootController in the root.py module. This is a hint to TG’s object dispatch controller to take over and do dispatch to the right controller method in root’s object hierarchy.
You can define custom middlware that does whatever you want it to do and pass into the application constructor in app_cfg.py. It will then be placed at this point in the stack so you have access to automatic database transactions, sessions, the cache and all of the other stuff added by previous middleware.
If you prefer to have more control over where your middleware is placed in the stack, you can do that by subclassing AppConfig or overriding methods on the base_config object.
Looks up a WSGIController object based on the info from Routes and calls it. By default this is an ObjectDispatchController that’s pulled into your app from lib/base so that you can override it if you need to.
But if necessary, you can replace with something more application specific.
The ObjectDispatchController’s job is to take the WSGI interface and adapt it to the way TG methods behave (dealing with templates and returned dicts, etc), and to do object based dispatch like CherryPy did in TurboGears 1.
The ObjectDispatchController’s functionality is broken into three basic pieces. The root PylonsController implements a WSGI interface, and actually calls the controller methods with params from routes. TG provides a DecoratedController. Decorated Controller allows you to use TG1 style decorations (@expose(), @validate etc.) on your controller methods, but does nothing for dispatch.
All of the dispatch is done by the Object Dispatch Controller and some associated functions that help with lookup.
The @expose and @validate decorators in TG2 are not function wrappers in the same way that they were in TG1. They merely register information about how that method ought to be called in it’s associated decorator diagram. This is brought up here because they influence the way that the Controller calls your code and handles the response. Expose determines how the dictonary returned by the controller is rendered into a WSGI response. If you return a string, or a WebOb webob.Response object, expose will not change your returned results at all.
The @validate in turn makes sure the form post or get query parameters are converted to python objects on the way in, or it will redirect the request to an optional error handler method.
All this is covered in much more depth in the Writing Controller Methods methods doc.
At this point we’ve arrived at your controller code, and it’s run. The details of all of this are covered here: Writing Controller Methods
Hopefully this helps you understand the flow of the request through the stack, and gives you some hints on how you can modify or customize the stack to meet your needs.
For details on exactly how the stack is configured take a look at the configuration docs at TurboGears 2 Configuration. | http://www.turbogears.org/2.1/docs/main/RequestFlow.html | CC-MAIN-2014-42 | refinedweb | 1,951 | 57.71 |
David Miller wrote:> From: Mark Lord <lkml@rtr.ca>> Date: Thu, 10 Apr 2008 20:16:11 -0400> >> [c67499c0e772064b37ad75eb69b28fc218752636 is first bad commit>> commit c67499c0e772064b37ad75eb69b28fc218752636>> Author: Pavel Emelyanov <xemul@openvz.org>>> Date: Thu Jan 31 05:06:40 2008 -0800>>>> [NETNS]: Tcp-v4 sockets per-net lookup.>>>> Add a net argument to inet_lookup and propagate it further>> into lookup calls. Plus tune the __inet_check_established.>>>> The dccp and inet_diag, which use that lookup functions>> pass the init_net into them.>>>> Signed-off-by: Pavel Emelyanov <xemul@openvz.org>>> Signed-off-by: David S. Miller <davem@davemloft.net>> > Thanks Mark.> > Pavel can you take a look? I suspect that the namespace> changes or gets NULL'd out somehow and this leads to the> resets because the socket can no longer be found. Perhaps> it's even a problem with time-wait socket namespace> propagation...My system here is now set up for quick/easy retest, if you have anysuggestions or patches to try out.Thanks guys. | http://lkml.org/lkml/2008/4/10/392 | CC-MAIN-2015-22 | refinedweb | 163 | 77.53 |
28 June 2011 11:37 [Source: ICIS news]
SINGAPORE (ICIS)--Bosch Solar Energy will invest €520m ($742m) to build a new photovoltaics manufacturing site at Penang in ?xml:namespace>
Construction of the new manufacturing site will begin before the end of this year, the source said.
Production at the new site is expected to begin by the fourth quarter of 2013, she added.
The completion of the entire site is expected to be completed in 2014 but no firm dates have been fixed, according to the source.
“The planned facility will cover the entire value-added chain, from silicon crystals and solar cells, to the modules which can be installed on roofs or in solar power plants,” said Holger von Hebel, chairman of Bosch Solar Energy, in an earlier statement.
Once fully functional, the manufacturing site will supply enough solar panels to power 300,000 Malaysian homes, the statement added.
The site’s output of photovoltaics products will also mainly serve
Bosch Solar Energy is the newest business division of Germany-based Bosch Group.
( | http://www.icis.com/Articles/2011/06/28/9473021/germanys-bosch-solar-energy-to-invest-in-malaysia-photovoltaics-site.html | CC-MAIN-2013-48 | refinedweb | 174 | 55.68 |
Performance
This guide describes how different of areas can influence the performance of the editor and what you can do to optimize those areas. It goes into how XPath can be optimized to improve your editor and suggests some other features to use make make the editor perform better.
X
Paths and performance
Fonto Editor uses XPaths for a lot of APIs. Most of these trigger an update when the result changes because of user input. Fonto Editor does this by recording which DOM properties are accessed by an XPath query.
We have explained our approach in more detail during XML Prague 2017.
Fonto Editor.
To get more insight into how XPath influence the performance of your editor, take a look at start, the XPath query
/metadata/article/other will perform better than
//article.
Ordering of operands
Our XPath implementation evaluates binary boolean operands (and, or) left to right. This can be leveraged to optimize some XPath queries.
Other
self::someElement[(let $id := @id return //@idref=$id) and @needsRef]
This XPath needs a full document scan, even if the
@needs attribute is absent. By swapping the operands around, the XPath can skip the next operand.
Other
We recommend introducing an attribute index to prevent full document scans. Instead of writing
//[@id=$rid] you can prevent the full document scan by adding a index on the id attribute and writing
my-namespace:id($id).
Buckets
Especially with CVK and SVK configuration, Fonto Editor the editor is heavily optimized, having to compute the state of a lot of buttons will cost some time.
The editor.
Collapsible
Tables
Tables are often one of the most performance demanding elements on a document, for this reason it is advised to use collapsible tables whenever possible. Collapsible tables are evaluated Just-In-Time and are only evaluated when they are not collapsed. This means that when tables are collapsed, the document does not experience any performance demands from those tables. This can drastically improve the overall editor performance depending on how the tables were being used.
Refer to this guide on how to configure and use collapsible tables.
Other performance improvements
It is advised to use label query widgets instead of custom widgets whenever possible. They are evaluated lazily and are only calculated when they are in view and in doing so they provide a better editor experience and lower initial document load time than custom widgets. | https://documentation.fontoxml.com/latest/performance-a2c8c8d819cd | CC-MAIN-2021-17 | refinedweb | 401 | 52.6 |
In Part III, I'm going to introduce some extensions to unit testing that, in my opinion, make unit testing more useful for the kind of work that I do.
I've extended the UI by adding tab pages for the pass, ignore, and fail states. Test fixtures and their tests are now alphabetized (although not necessarily run in alphabetical order--the sorting is done by the UI, not the unit test library). And finally, I've added a few features that are reflected in the UI as well.
Most of what I code (and I imagine what other people code) is two things:
And a lot of times, the process is something that involves the user's interaction. An example of a very simple linear process is a wizard dialog, which prompts the user through a configuration in a very predictable and regimented manner. The automatic billing case study that I've been using in these articles is an example of a potentially less linear process. Especially when there's a lot of user interaction, the software has to be made a lot more robust (and flexible) in order to accommodate the different ways that the user is going to interact with the program. The programming bug in the Therac-25 that resulted in radiation overdose is a good example--the interface involved a concurrent system and failed if the operator corrected an input error within 8 seconds of entering the mistake. In this particular example:.1
On the other hand, the X-43A mishap, in which a hypersonic air-breathing flight vehicle lost control in an unmanned test, was blamed not on the failure to test separate modules, but the failure to properly test the system as a whole:.2
So here we have two different examples of how, while testing certainly was done, it wasn't done in the right way--people lost their lives and taxpayers saw their money going up in smoke.
Now, returning to the mundane, I have in the previous two articles on Unit Testing:
But are my unit tests really all that good? The overall process (automatic billing) consists of a lot of different steps, involves many components, and involves a lot of user interaction:
There's a lot that can go wrong here, that must be done in a particular order, and that are susceptible to the system changing because of the time it takes to complete the process Consider that it can take weeks for a part to arrive after it's been purchased, and several more weeks after that to receive the invoice. Or, as sometimes happens, the invoice comes in before the part has been received! Now, my case study is definitely a simplified version of the purchasing/receiving/billing process at the boatyard where I've written their yard management software, but even simplified, it is a good illustration for the purposes of exploring unit testing.
There's a lot of repetition involved in my case study. For example, testing whether the
ClosePO function works involves setting up:
But all this was already done as part of unit testing the individual work orders, parts, vendors, invoices, and charges. Why not just combine these steps into a single process?
A process is an ordered sequence of unit tests. As long as one test passes, the next test is run. This requires several modifications to MUTE:
An in sequence process is one that runs in the order specified by the programmer who wrote the unit tests. Each unit test typically builds on information verified by the previous unit test. When a unit test fails, the remaining unit tests in the sequence are designated as "not run" because it would be pointless to run them. This is displayed with a blue circle for each test not run. For example:
and the tests not run are listed in the "Not Run" tab:
The question then becomes, what do you test in order to ensure that the code handles itself well when the user or the program does something in an unexpected way (out of sequence)? Obviously, testing all the combinations is not acceptable. The purchase order sequence test that I wrote involves 16 steps, and testing every combination of 16 steps is 16!, or 20,922,789,888,000 (that's almost 21 trillion cases!).
What does "out of sequence" mean? It means that a piece of code is run before another piece of code. This clearly reduces the number of combinations that have to be analyzed, because the total combinations includes numerous combinations in which some code is still run in sequence, and we're not interested in those because we know that the "in sequence" parts of the process already pass! There is only one combination that runs all the code out of sequence, and that's the combination in which the process is run in reverse. So, there are only two tests that need to be performed--forward, in which the process is run forward, and reverse, in which the process is run backwards.
OK, this isn't entirely true. It is easily possible, for example, to have a piece of code dependent upon two or more external objects. Testing only in reverse order catches only the first dependency. Clearly, to catch the second dependency, at least one predecessor (in sequence) must be run. This condition is not handled in this version (yes, yes, I'll be adding it in the next version as soon as I've put some thought into the implementation issues).
This is something that is very worthy of additional unit test extensions, but I'm not going to get into the issues involved at this point. Let's keep things simple for now!
To support all this, we need some new attributes.
[AttributeUsage(AttributeTargets.Class, AllowMultiple=false, Inherited=true)] public sealed class ProcessTestAttribute : Attribute { }
This attribute is attached to a test fixture (a class) to indicate to the test runner that the tests should be run in the order specified by the programmer. For example:
[TestFixture] [ProcessTest] public class POSequenceTest { ... }
[AttributeUsage(AttributeTargets.Method, AllowMultiple=false, Inherited=true)] public sealed class SequenceAttribute : Attribute { private int order; public int Order { get {return order;} } public SequenceAttribute(int i) { order=i; } }
This attribute is specified for each test case in the process test fixture, numbered from 1 to the number of test cases. For example:
[Test, Sequence(1)] public void POConstructor() { po=new PurchaseOrder(); Assertion.Assert(po.Number=="", "Number not initialized."); Assertion.Assert(po.PartCount==0, "PartCount not initialized."); Assertion.Assert(po.ChargeCount==0, "ChargeCount not initialized."); Assertion.Assert(po.Invoice==null, "Invoice not initialized."); Assertion.Assert(po.Vendor==null, "Vendor not initialized."); } [Test, Sequence(2)] public void VendorConstructor() { vendor=new Vendor(); Assertion.Assert(vendor.Name=="", "Name is not an empty string."); Assertion.Assert(vendor.PartCount==0, "PartCount is not zero."); } [Test, Sequence(3)] public void PartConstructor() { part1=new Part(); Assertion.Assert(part1.VendorCost==0, "VendorCost is not zero."); Assertion.Assert(part1.Taxable==false, "Taxable is not false."); Assertion.Assert(part1.InternalCost==0, "InternalCost is not zero."); Assertion.Assert(part1.Markup==0, "Markup is not zero."); Assertion.Assert(part1.Number=="", "Number is not an empty string."); part2=new Part(); part3=new Part(); } ...
The world is not perfect, and, when running our unit tests in reverse, we don't want the unit test to fail, we want to see if the code being tested fails. Therefore, there are cases when it is necessary to execute some code earlier in the process in order to ensure that the unit test, which depends on this code, doesn't break. This attribute handles that. For example:
[Test, Sequence(4), Requires("PartConstructor")] public void PartInitialization() { part1.Number="A"; part1.VendorCost=15; Assertion.Assert(part1.Number=="A", "Number did not get set."); Assertion.Assert(part1.VendorCost==15, "VendorCost did not get set."); part2.Number="B"; part2.VendorCost=20; part3.Number="C"; part3.VendorCost=25; }
In order to initialize a part, well, that part has to be constructed first! Therefore, this unit test requires that the constructor test be run first.
It is very easy to fall into the idea that, for example, closing the PO requires that parts and charges have been assigned to the PO. This is NOT how the
Requires attribute should be used, because all this does is ensure that the process is run in a forward direction. Rather, this attribute should be used to ensure that parameters that the unit test code needs are already in existence. The only thing I've ever needed the
Requires attribute for is to guarantee that an object exists to which the unit test is about to assign a literal. Contrast the above example with the following code:
[Test, Sequence(15), Requires("POConstructor")] public void AddInvoiceToPO() { po.Invoice=invoice; Assertion.Assert(invoice.Number==po.Invoice.Number,
"Invoice not set correctly."); }
Here, we do NOT require that the invoice object be constructed. The property should validate this for itself. However, we DO require that the purchase order object be prior constructed. A simple "l-value" rule is sufficient to determine if the
Requires attribute needs to be used--if the object is on the left side of the equal sign, then yes. If it is on the right side of the equal sign, then no.
Note that in the definition of the
Requires attribute:
[AttributeUsage(AttributeTargets.Method, AllowMultiple=true, Inherited=true)] public sealed class RequiresAttribute : Attribute { private string priorTestMethod; public string PriorTestMethod { get {return priorTestMethod;} } public RequiresAttribute(string methodName) { priorTestMethod=methodName; } }
multiple attributes may be assigned to the same test. For example:
[Test] [Sequence(16)] [Requires("POConstructor")] [Requires("WorkOrderConstructor")] public void ClosePO() { ... }
[AttributeUsage(AttributeTargets.Method, AllowMultiple=false, Inherited=true)] public sealed class ReverseProcessExpectedExceptionAttribute : Attribute { private Type expectedException; public Type ExceptionType { get {return expectedException;} } public ReverseProcessExpectedExceptionAttribute(Type exception) { expectedException=exception; } }
In a regular unit test, the
ExpectedException attribute is used to ensure that the code under test throws the appropriate exception because the unit test is setting up a failure case. Process tests are set up to succeed--in other words, there shouldn't be any exceptions thrown when the process is run in the forward direction (individual tests that throw exceptions are still part of other unit tests). Testing a process in the reverse direction may cause once working code to fail, hopefully with an exception thrown by the code, not the framework. To test this, the
ReverseProcessExpectedException attribute has been added to make sure that the code handles and out of order process.
Using the automatic billing case study I've been developing in Parts I and II, I wrote a process test that goes through all the steps involved in getting to the point where the PO can be closed. Compare this code to the
ClosePO unit test written in Part II:
[Test] [Sequence(16)] [Requires("POConstructor")] [Requires("WorkOrderConstructor")] public void ClosePO() { po.Close(); // one charge slip should be added to both work orders Assertion.Assert(wo1.ChargeSlipCount==1,
"First work order: ChargeSlipCount not 1."); Assertion.Assert(wo2.ChargeSlipCount==1,
"Second work order: ChargeSlipCount not 1."); ... }
Note that all the setup stuff has already been done. A lot simpler, isn't it?
Running this process in the forward direction, everyone is happy:
Now let's look at what happens when I run the process in reverse:
Yuck! Obviously, my code does not handle things being done in the wrong order very well! Inspecting the failures:
makes it obvious that I'm not handling un-initialized objects very well at all. Time to fix those.
An exception is thrown if the invoice does not already exist:
if (invoice==null) { throw(new InvalidInvoiceException()); }
This is an important issue to note to the user--a PO cannot be closed without having an invoice against that PO!
This illustrates the usefulness of testing property assignments. It could easily have been the unit test itself that was throwing an exception because the the property assignment is not checking to see if the object being passed to it is a valid object! To fix this, the assignment is modified:
public Invoice Invoice { get {return invoice;} set { if (value==null) { throw(new InvalidInvoiceException()); } else if (value.Number=="") { throw(new UnassignedInvoiceException()); } // *** NO VENDOR TEST !!! *** if (value.Vendor.Name != vendor.Name) { throw(new DifferentVendorException()); } invoice=value; } }
This issue is complicated by the fact that it is often common practice to "overload information". Meaning that, if the purchase order returns a NULL, it means that the invoice hasn't yet been set. While this is easy coding practice, it isn't a good practice. A method like:
public bool InvoiceExists(void) {return value != null;}
is a much better solution. Then, the getter can throw an exception if the caller is about to get inappropriate data.
The same issues present themselves here and are easily corrected:
public void Add(Charge c) { if (c==null) { throw(new InvalidChargeException()); } if (c.Description=="") { throw(new UnassignedChargeException()); } charges.Add(c); }
This points out the benefits of a "has a" relationship--the wrapping class can perform data validation that would otherwise not be possible.
Here we have a case where the unit test is throwing an exception because the
Invoice class is not testing for valid data. This is easily fixed:
public Vendor Vendor { get {return vendor;} set { if (value==null) { throw(new InvalidVendorException()); } vendor=value; } }
A couple data validation tests are added to fix this problem:
public void Add(Part p, WorkOrder wo) { if (p==null) { throw(new InvalidPartException()); } if (wo==null) { throw(new InvalidWorkOrderException()); } if (p.Number=="") { throw(new UnassignedPartException()); } if (wo.Number=="") { throw(new UnassignedWorkOrderException()); } if (!vendor.Find(p)) { throw(new PartNotFromVendorException()); } parts.Add(p, wo); partsArray.Add(p); }
More of the same...
public void Add(Part p) { if (p==null) { throw(new InvalidPartException()); } if (p.Number=="") { throw(new UnassignedPartException()); } if (parts.Contains(p.Number)) { throw(new DuplicatePartException()); } parts.Add(p.Number, p); partsArray.Add(p); }
Running the process is reverse now works, in the sense that all the bad data is validated and the proper exceptions are thrown.
Unit testing really brings to the forefront the difference between using assertions (or program by contract) and throwing exceptions (let the caller handle the error). This doesn't mean that programming by contract requires using assertions--rather, it means that programming by contract shoud not use assertions but rather throw exceptions. The reason for this is simple--the unit test itself uses assertions to validate data and expects exceptions to be thrown if the unit under test detects a fault. The unit test then verifies that the exception is expected or not.
Throwing exceptions results in more robust code. The exception tests can (and should!) be left in production code, so that the higher level functions can gracefully report problems to the user and take corrective actions. Asserts, when they are removed in production code, simply result in program crashes or erroneous operations when the unexpected happens (which inevitably does).
Using unit testing principles therefore, asserts are quickly going to go the way of the dinosaur. (Disagreements???)
As it currently stands, the code is not very robust. It doesn't verify that
Requiresfunctions actually exist.
In other words, some unit tests really need to be written for this thing! Well, in the next release, it'll be a bit more bullet proofed.
Well, part IV is not going to talk about scripting. Part IV is going to look at some other useful additions to unit testing. Hopefully the next part can wrap up those extensions (this one issue was worthy of an article in itself, in my opinion), so hopefully Part V will cover scripted unit testing.
Footnotes
1 -
cpe9001/assets/readings/www_uguelph_ca_~tgallagh_~tgallagh.html
2 -
References
Checking High-Level Protocols in Low-Level Software:
Programming By Contract:
General
News
Question
Answer
Joke
Rant
Admin | http://www.codeproject.com/KB/cs/autp3.aspx | crawl-002 | refinedweb | 2,630 | 54.32 |
51481/what-is-list-comprehension
List comprehensions are used for creating new list from another iterables. As list comprehension returns list, they consists of brackets containing the expression which needs to be executed for each element along with the for loop to iterate over each element
A list comprehension generally consist of these parts :
Output expression,
input sequence,
a variable representing member of input sequence and
an optional predicate part.
Lists are mutable(values can be changed) whereas ...READ MORE
Hi. Nice question.
Here is the simplified answer ...READ MORE
Lists and arrays are used in Python ...READ MORE
How am i supposed list all the ...READ MORE
suppose you have a string with a ...READ MORE
You can also use the random library's ...READ MORE
Syntax :
list. count(value)
Code:
colors = ['red', 'green', ...READ MORE
can you give an example using a ...READ MORE
Execute the following command on your terminal:
python ...READ MORE
import pandas
df = pd.read_csv('filename')
it will give attribute ...READ MORE
OR
At least 1 upper-case and 1 lower-case letter
Minimum 8 characters and Maximum 50 characters
Already have an account? Sign in. | https://www.edureka.co/community/51481/what-is-list-comprehension | CC-MAIN-2021-43 | refinedweb | 192 | 60.01 |
Next: Key Binding Conventions, Up: Tips
Here are conventions that you should follow when writing Emacs Lisp code intended for widespread use:
This convention is mandatory for any file that includes custom definitions. If fixing such a file to follow this convention requires an incompatible change, go ahead and make the incompatible change; don't postpone it.
Occasionally, for a command name intended for users to use, it is more convenient if some words come before the package's name prefix. And constructs that define functions, variables, etc., work better if they start with ‘defun’ or ‘defvar’, so put the name prefix later on in the name.
This recommendation applies even to names for traditional Lisp
primitives that are not primitives in Emacs Lisp—such as
copy-list. Believe it or not, there is more than one plausible
way to define
copy-list. Play it safe; append your name prefix
to produce a name like
foo-copy-list or
mylib-copy-list
instead.
If you write a function that you think ought to be added to Emacs under
a certain name, such as
twiddle-files, don't call it by that name
in your program. Call it
mylib-twiddle-files in your program,
and send mail to ‘bug-gnu-emacs@gnu.org’ suggesting we add
it to Emacs. If and when we do, we can change the name easily enough.
If one prefix is insufficient, your package can use two or three alternative common prefixes, so long as they make sense.
provideat the end of each separate Lisp file. See Named Features.
requireto make sure they are loaded. See Named Features.
(eval-when-compile (require 'bar))
This tells Emacs to load bar just before byte-compiling
foo, so that the macro definition is available during
compilation. Using
eval-when-compile avoids loading bar
when the compiled version of foo is used. It should be
called before the first use of the macro in the file. See Compiling Macros.
requirethat library at the top-level and be done with it. But if your file contains several independent features, and only one or two require the extra library, then consider putting
requirestatements inside the relevant functions rather than at the top-level. Or use
autoloadstatements to load the extra library when needed. This way people who don't use those aspects of your file do not need to load the extra library.
cl-liblibrary rather than the old
cllibrary. The latter does not use a clean namespace (i.e., its definitions do not start with a ‘cl-’ prefix). If your package loads
clat run time, that could cause name clashes for users who don't use that package.
There is no problem with using the
cl package at compile
time, with
(eval-when-compile (require 'cl)). That's
sufficient for using the macros in the
cl package, because the
compiler expands them before generating the byte-code. It is still
better to use the more modern
cl-lib in this case, though.
framepand
frame-live-p.
-unload-hook, where feature is the name of the feature the package provides, and make it undo any such changes. Using
unload-featureto unload the file will run this function. See Unloading.
(defalias 'gnus-point-at-bol (if (fboundp 'point-at-bol) 'point-at-bol 'line-beginning-position))
eval-after-loadin libraries and packages (see Hooks for Loading). This feature is meant for personal customizations; using it in a Lisp program is unclean, because it modifies the behavior of another Lisp file in a way that's not visible in that file. This is an obstacle for debugging, much like advising a function in the other package.
utf-8-emacs(see Coding System Basics), and specify that coding in the ‘-*-’ line or the local variables list. See Local Variables in Files.
;; XXX.el -*- coding: utf-8-emacs; -*- | http://www.gnu.org/software/emacs/manual/html_node/elisp/Coding-Conventions.html | CC-MAIN-2013-20 | refinedweb | 641 | 65.01 |
Back to the GarbageCollectorNotes
Motivation For Parallelization
The essential idea is best described here: [refer to the flood paper]
It is helpful to be aware of copy collection and mark-compact collection before you read the above paper. The Richard Jones and Raphael Lins text on Garbage Collection is a recommended resource.
For our garbage collector, we are yet to work out the details of how Gen0 should be compacted. The best idea for later generations is some variant of the work stealing approach proposed in the above paper. This of course might change in the course of the project.
Measurement of Block Distance while Scavenging
Here are some plots of block distance against the collection number and the average block distance and the collection number. Block distance is defined to be the number of links one has to follow from the scan_bd to reach the hp_bd in a step during garbage collection. If the block distance in 2 then it means that there is atleast one independent block in between the pointers that can be taken up by another thread.
The essential idea behind work stealing is that free threads can steal work from busy threads. The work is essentially the work of scavenging live objects. hp_bd points to the top of the to-space where the next free object can go. scan_bd points to the block where the next object to be scanned is. All objects between scan_bd and hp_bd are objects that are yet to be scanned. A free thread essentially steal a block of objects in this range and can scan them, essentially reducing the load of the busy thread.
The following program was used to generate some the graphs below. Changing the treeDepth and the nTrees values below one can get the program to have different memory profiles.
import System treeDepth = 17 nTrees = 40 makeList 0 d = [] makeList n d = d : (makeList (n-1) d) main :: IO () main = if (recVal (makeList nTrees treeDepth)) < 10 then print "###" else print "##" data Tree a = L a | B (Tree a) (Tree a) makeTree 0 = L 1 makeTree n = B (makeTree (n-1)) (makeTree (n-1)) sumTree (L x) = x sumTree (B t1 t2) = 1 + (sumTree t1) + (sumTree t2) treeVal n rest = let tr1 = makeTree n in sumTree(tr1) + sumTree(makeTree n) + (recVal rest) + sumTree(tr1) recVal [] = 0 recVal (x:xs) = treeVal x xs
Here are some plots:
Here is how to interpret the graphs. The label ‘#’ on an axis indicates that it is time where each tick is a garbage collection. The label ‘live_objs’ indicates the total number of live objects encountered during this collection. This is not the total number of live objects in the system but only those in the generations currently collected. The value ‘block_dist’ indicates the maximum block distance encountered during a collection.
The value `avg_block_dist’ indicates the average block distance encountered during a collection. If you think about the block distance a bit you realize that it essentially starts from zero increases and decreases during the duration of scavenging and finally becomes zero when the scan point catches up with the heap pointer. We wanted to measure approximately the area under this region as a indication of the average chance of parallelization. Further to make the measurement a little less fine grained, it was taken only when a new block was allocated to the to-space. This value can be considered indicative of how much parallelization is possible on average during that GC run. [At least I hope so]
Here are similar plots of some programs in the nofib test suite that is available in the GHC source tree.
Plots of real/fulsom (with input 8)
Plots of real/pic (with input 20000)
Plots of real/fem (with fem.stdin)
fem did not do any G1 collections.
Roshan James (rpjames [at] cs [dot] indiana [dot] edu) | https://ghc.haskell.org/trac/ghc/wiki/MotivationForParallelization?version=4 | CC-MAIN-2015-27 | refinedweb | 642 | 67.18 |
The new C++ standard includes a couple Python-like features that I ran across recently. There are other Python-like features in the new standard, but here I’ll discuss range-based for-loops and raw strings.
In Python you loop over lists rather than incrementing a loop counter variable. For example,
for p in [2, 3, 5, 7, 11]: print p
Range-based for loops now let you do something similar in C++11:
int primes[5] = {2, 3, 5, 7, 11}; for (int &p : primes) cout << p << "n";
Also, Python has raw strings. If you preface a quoted string with
R, the contents of the string is interpreted literally. For example,
print "Hello\nworld"
will produce
Hello world
but
print R"Hello\nworld"
will produce
Hello\nworld
because the \
n is no longer interpreted as a newline character but instead printed literally as two characters.
Raw strings in C++11 use
R as well, but they also require a delimiter inside the quotation marks. For example,
cout << R"(Hello\nworld)";
The C++ raw string syntax is a little harder to read than the Python counterpart since it requires parentheses. The advantage, however, is that such strings can contain double quotes since a double quote alone does not terminate the string. For example,
cout << R"(Hello "world")";
would print
Hello "world"
In Python this is unnecessary since single and double quotes are interchangeable; if you wanted double quotes inside your string, you’d use single quotes on the outside.
Note that raw strings in C++ require a capital
R unlike Python that allows
r or
R.
The C++ features mentioned here are supported gcc 4.6.0. The MinGW version of gcc for Windows is available here. To use C++11 features in gcc, you must add the parameter
-std=c++0x to the
g++ command line. For example,
g++ -std=c++0x hello.cpp
Visual Studio 2010 supports many of the new C++ features, but not the ones discussed here.
Related links:
10 thoughts on “A couple Python-like features in C++11”
Nice writeup, John. I just wanted to point out that the style of for iterating over a sequence has been around way before Python, at least since the Bourne shell. Also, the syntax for C++11’s range-based for is actually more reminiscent of Java’s for-each loop (not that you claimed otherwise).
Raw strings in Python aren’t as raw as you describe them here.
See e.g. “(even a raw string cannot end in an odd number of backslashes)” from
The features in the new C++ are not as new as I think. Anyways great post!
Oh great: yet another raw string syntax to learn/ Shouldn’t complain, I guess. At least it’s there.
Nitpicking here: Visual Studio 2010 supports many of the new C++ features, but it not the ones discussed here.
Should be: Visual Studio 2010 supports many of the new C++ features, but not the ones discussed here.
Failed to mention in my previous comment. I always like the articles you write :)
Thanks for sharing your knowledge.
I never liked C– and this post cannot change anything.
Look at C– template structure and sample codes, it is a piece of rubbish.
Cheers,
Hi John,
I just stumbled upon this post and wanted to share a new feature in C++11 as well by modifying your iteration snippet from above. If you want C++ to automatically pick the correct iterator type for you, you can use the
autokeyword (note the different meaning in C++ compared to C:). This is very helpful when having to iterate over template containers. When coming from Python, one might also like the lambda functions in C++11.
Thanks for your post!
Konrad
#include
#include
using namespace std;
int main(int argc, char *argv[]) {
int primes[] = {2, 3, 5, 7, 11};
// Iteration with explicit type specification
for (int &p : primes)
cout << p << endl;
// Iteration with implicit type specification
// (using "auto" keyword)
for (auto &p : primes)
cout << p << endl;
// Iteration with lambda function
auto my_lambda = [](int &p){ cout << p << endl; };
for (auto &p : primes)
my_lambda(p);
// Iteration using "for_each" algorithm
// and lambda function
for_each(primes, primes+5, my_lambda);
return 0;
} | https://www.johndcook.com/blog/2011/08/17/a-couple-python-like-features-in-c11/ | CC-MAIN-2021-49 | refinedweb | 705 | 69.72 |
fixed 1.0dev
A library for quickly processing fixed width files.
This package provides tools for building fast parsers of files composed of fields width records where one of the fields in the record specifies what type of record the line is.
The parsers built using this package yield named tuples containing the information in each row.
The parsers are specified using a simple and succinct declarative style:
from fixed import Parser, Record, Field, Discriminator, Skip class Header(Record): type = Discriminator('H') row_count = Field(8, int) class Data(Record): type = Discriminator('D') source = Field(5) junk = Skip(10) destination = Field(5) parser = Parser(Header, Data)
- Author: Chris Withers
- License: MIT
- Categories
- Package Index Owner: chrisw
- DOAP record: fixed-1.0dev.xml | https://pypi.python.org/pypi/fixed/1.0dev | CC-MAIN-2016-44 | refinedweb | 121 | 52.53 |
This chapter shows you how to integrate design definitions from third-party design tools such as Oracle Designer.
This chapter includes the following:
Using Design Definitions from Oracle Designer 6i/9i
Example: Importing from CA Erwin
You can create a source module that connects to an Oracle Designer repository. When the definitions for an application are stored and managed in an Oracle Designer repository, the time required to connect to the application is reduced.
Designer 6i/9i repositories use workareas to control versions of an object. By selecting a workarea, you can specify a version of a repository object. With Designer 6i/9i, you can also group objects into container elements within workareas. Container Elements contain definitions for namespace and ownership of objects, and enable you to view objects even if they are owned by a different user. Because Designer 6i/9i container elements are controlled by workareas, they are version controlled. See the Designer 6i/9i documentation for more information about workareas and container elements.
All visible objects of a workarea or a container element in Designer 6i/9i are available for use as data sources. To select Designer 6i/9i objects as a source:
Specify a workarea, and
Specify the container element in the workarea
The Module Editor detects the Designer version to which you are connected. If it finds Designer 6i/9i, the Metadata Location tab shows two lists, Workarea and Container Element. When you select a workarea, the Container Element list will show the container elements in 6i/9i source, you must follow the steps outlined in "Importing Definitions from a Database".
To create a Designer 6i/9i source module:
Create a database source module.
Double-click the name of the newly created module to open the Module Editor.
In the Metadata Location tab, select the source type as Oracle Designer Repository. Also select the database location containing the Designer object.
When you select the source type as Oracle Designer Repository, two new lists, Workarea and Container Element, are visible in the Metadata Location tab.
Select the Designer 6i/9i object from the workarea and select the specific container element.
Figure 5-1 The Metadata Location Tab
Note:The database you specify as source must contain a Designer 6i/9i object. If not, then the Workarea and Element Container lists will be empty.
Click OK.
For related information, see the following sections:
Importing Definitions from a Database
Reimporting Definitions from an Oracle Database
Updating Oracle Database Source Definitions
A movie rental company uses tools from different vendors for data modelling, extraction, transformation and loading (ETL), and reporting purposes. Using a variety of tools has led to several metadata integration issues for this company. Often, the design work done using one tool cannot be completely integrated or reused in another. This company wants to find a method to streamline and integrate all its metadata designs and ETL processes using a single tool.
Warehouse Builder enables the company to import and integrate metadata designs from different tools and use them for data modelling and ETL purposes using only one tool. Warehouse Builder uses the seamlessly integrated technology from Meta Integration Technology Inc. (MITI) to import the metadata and reuse the data models designed by other third-party tools.
This case study shows you how to easily import design files developed using CA ERwin into Warehouse Builder. You can then reuse the metadata for ETL design and reporting using a single tool. You can follow this model to import files from other tools such as Sybase PowerDesigner and Business Objects Designer.
This case study shows you how the movie rental company can migrate their ERwin data model designs into Warehouse Builder. They can also use this model to import designs from other third party tools and consolidate their design metadata in a central workspace. Follow these steps:
Download Metadata from CA ERwin
Install the Meta Integration Model Bridge
Create an MDL File from the CA ERwin Data
Import the MDL file into Warehouse Builder
Use Warehouse Builder Transfer Wizard to import the ERwin metadata into Warehouse Builder.
Download Metadata from CA ERwin
Download the design metadata from CA ERwin to your local system.
Install the Meta Integration Model Bridge
Warehouse Builder enables you to integrate with Meta Integration Model Bridges (MIMB). These bridges translate metadata from a proprietary metadata file or repository to the standard CWM format that can be imported into Warehouse Builder using the Warehouse Builder Transfer Wizard. To import files from different design tools into Warehouse Builder, you must first obtain an MIMB license and install the bridges on your system. Follow these steps to complete the installation.
To download MIMB:
Download the Model Bridge must add it to the path:
c:\program files\metaintegration\win32
Create an MDL File from the CA ERwin Data
Create an MDL file from CA ERwin using Warehouse Builder.
After you install the MIMB product, follow these steps to create an MDL file from ERwin and other third party design tools:
From the Project Explorer, select and expand the Project node to which you want to import the metadata. In this example, the ERwin files are imported into
MY_PROJECT.
From the Design menu, select Import, Bridges to start the Warehouse Builder Transfer Wizard.
This wizard seamlessly integrates with the MITI technology to translate the third-party metadata into a standard CWM format that is imported into Warehouse Builder. Follow the wizard to complete the import.
In the Metadata Source and Target Identification page, select CA ERwin 4.0 SP1 to 4.1 in the From field.
In the Transfer Parameter Identification page, provide the path where the ERwin files are located in the Erwin4 Input File field. In this example, the company wants to import the
Emovies.xml file from ERwin.
Accept the default options for all other fields.
In the OWB Project field, enter the Warehouse Builder project where you want to import the ERwin file. In the Warehouse Builder MDL field, enter a name and select the location to store the .mdl file that will be generated.
Complete the remaining wizard steps and finish the import process.
Import the MDL file into Warehouse Builder
Import the MDL file to import metadata from the CA ERwin file into Warehouse Builder. To import the MDL file:
Select MY_PROJECT and from the Design menu, select Import, Warehouse Builder Metadata to open the Metadata Import dialog box.
In the File Name field, specify the name of the
mdl file you generated in "Create an MDL File from the CA ERwin Data".
Click Import to import the metadata into Warehouse Builder.
If the metadata file version and the workspace version are not compatible, then the Metadata Upgrade window pops up. Click Upgrade to upgrade the
.mdl file.
After you finish importing the ERwin files into Warehouse Builder, expand the MY_PROJECT folder, then the Databases node, and then the Oracle node. You can see the imported source metadata objects, as shown in Figure 5–2.
Figure 5-2 Metadata Objects Imported from CA Erwin
Double-click the table names to see the properties for each of these tables. Warehouse Builder imports all the metadata including descriptions and detailed information on table columns and constraints, as shown in Figure 5–3.
Figure 5-3 Table Properties Imported from CA Erwin
The designers at the movie rental company can use these sources tables to model ETL designs in Warehouse Builder, generate ETL code, and run reports on them. Furthermore, Warehouse Builder enables them to easily import all the scattered third-party design metadata and consolidate all their design and development efforts. | http://docs.oracle.com/cd/B28359_01/owb.111/b31278/ref_imp_thirdparty_design.htm | CC-MAIN-2016-18 | refinedweb | 1,265 | 53 |
Scope: Composition between classes in C++
Audience: Those who have a basic understanding of classes, and pass by value functions.
Specs: Written with the C++ Standard Library. Compiled in VS2008 C++ Express Edition.
Implementation: When creating classes, we aim to have each class perform one function. For more complex problems, one solution is to use composition. I use the ol' computer example. A computer performs many operations. It directs the flow of data, saves and retrieves data, provides a UI for input/output. Instead of writing one giant class for handling all of these operations, we could break this into multiple classes that handle objects between eachother. Below are three files that represent a simple example of such. There is main.cpp which provides the UI, CPU.h which directs objects to they're proper class, and Storage.h which accepts the data in this scenario. This is a simple example, but it gives you an idea of how Composition can make your complex class more simple to maintain through sub-classes.
main.cpp
//Composition #include<iostream> #include<string> #include<stdlib.h> #include"CPU.h" using namespace std; int main() { int val = 0; string choice; for(int j = 0; j < 5; j++) { cout<<"Booting..."<<endl; } cout<<"Boot Success!"<<endl; cout<<endl; cout<<"\nPress any key to continue..."<<endl; cin.get(); //system("CLS"); //Uncomment if running Windows cout<<endl; cout<<"Welcome User, you may now store numerical data."<<endl; cout<<endl; do { cout<<endl; cout<<"Please enter a number to save to disk."<<endl; cout<<endl; if(!(cin>>val)) { cout<<endl; cout<<"Invalid Input"<<endl; return 0; } else cout<<endl; cout<<"Saving..."<<endl; cout<<endl; CPU beginProc((Storage(val))); //explicitly initialize CPU cout<<endl; //to pass val to class Storage cout<<"Would you like to save another number? (y or n)"<<endl; cout<<endl; cin>>choice; //system("CLS"); //Uncomment if running Windows }while(choice=="y"); cout<<endl; cout<<"Goodbye"<<endl; cout<<endl; cin.get(); return 0; }
cpu.h
#ifndef CPU_H #define CPU_H #include<iostream> #include"Storage.h" //Must include Storage.h to allow //passing of object from CPU class CPU { Storage objPass; public: CPU(){}; CPU(const Storage &obj) : objPass(obj) //creating a reference to { //storage class, allow initialization } //of passed object to storage ~CPU() { } }; #endif
storage.h
#ifndef STORAGE_H #define STORAGE_H #include<iostream> class Storage { int store; public: Storage() : store(0) { } Storage(int passIn) : store(passIn) //Since an int was passed out of { //main(), we accept an int in storage std::cout<<store<<" has been saved to disk.\n"; } ~Storage(){}; }; #endif | http://www.dreamincode.net/forums/topic/181180-composition/page__pid__1063252__st__0 | CC-MAIN-2016-18 | refinedweb | 420 | 60.01 |
Opened 4 years ago
Closed 4 years ago
Last modified 4 years ago
#7556 closed defect (fixed)
[Patch] Vote counter problem in trac 0.12
Description
I'm getting an issue with this plugin with trac 0.12. After installing this plugin it does not update the vote counter when clicked on, in my installation. However when I reload the page the vote counter is incremented. When investigating my trac log I found it was generating the following error.
File "build\bdist.win32\egg\tracvote\__init__.py", line 152, in process_request body, title))) File "c:\docume~1\lp03\locals~1\temp\1\easy_install-kpxh76\Trac-0.12-py2.7-win32.egg.tmp\trac\web\api.py", line 412, in send self.write(content) File "c:\docume~1\lp03\locals~1\temp\1\easy_install-kpxh76\Trac-0.12-py2.7-win32.egg.tmp\trac\web\api.py", line 530, in write raise ValueError("Can't send unicode content") ValueError: Can't send unicode content
On further investigation I think this is related to an API change in 0.12 to refuse taking unicode see
To fix it, for now, I've changed the function process_request, in the __init__.py file along similar lines as suggested in the above link. i.e. I convert the string passed to req.send to utf-8 if in an unicode format. See new process_request function below...
def process_request(self, req): req.perm.require('VOTE_MODIFY') match = self.path_match.match(req.path_info) vote, resource = match.groups() resource = self.normalise_resource(resource) vote = vote == 'up' and +1 or -1 old_vote = self.get_vote(req, resource) if old_vote == vote: vote = 0 self.set_vote(req, resource, 0) else: self.set_vote(req, resource, vote) if req.args.get('js'): body, title = self.format_votes(resource) content = ':'.join((req.href.chrome('vote/' + self.image_map[vote][0]), req.href.chrome('vote/' + self.image_map[vote][1]), body, title)); if isinstance(content, unicode): content = content.encode('utf-8') req.send(content); req.redirect(resource)
Attachments (0)
Change History (7)
comment:1 Changed 4 years ago by rjollos
- Summary changed from vote counter problem in trac 0.12 (uni to [Patch] Vote counter problem in trac 0.12
comment:2 Changed 4 years ago by rjollos
Reassigning ticket to new maintainer.
comment:3 Changed 4 years ago by rjollos
- Status changed from new to assigned
I've reproduced the issue with Trac 0.12.1dev-r10015 and confirmed that your patch works. Thank you for the excellent research on this one!
comment:4 Changed 4 years ago by rjollos
- Resolution set to fixed
- Status changed from assigned to closed
comment:5 Changed 4 years ago by rjollos
Confirmed that VotePlugin still works in Trac 0.11.7.
comment:6 Changed 4 years ago by rjollos
Added PeterLawrence to list of contributors on project wiki page.
Thanks for the patch! I will look at integrating it to a 0.12 branch very soon. | http://trac-hacks.org/ticket/7556 | CC-MAIN-2014-52 | refinedweb | 483 | 60.92 |
What is the output of this code snippet?
[python]
def fibo(n):
result = []
a, b = 0, 1
while a < n:
result.append(a)
a, b = b, a+b
return result
fib100 = fibo(100)
print(fib100[-1]==
fib100[-2]+fib100[-3])
[/python]
Recap, the Fibonacci series is the series of numbers that arises when repeatedly summing up the last two numbers starting from 0 and 1. The
fibo function in the puzzle calculates all Fibonacci numbers up to the function argument n. We use the concise method of multiple assignment to store the value of b in the variable a and to calculate the new value of b as the sum of both. We maintain the whole sequence in the list variable
result by appending the sequence value a to the end of the list.
The puzzle calculates the Fibonacci sequence up to 100 and stores the whole list in the variable
fib100. But to solve the puzzle, you do not have to calculate the whole sequence. The print statement only compares whether the last element is equal to the sum of the second and third last element in the sequence. This is true by definition of the Fibonacci series.
Humans can solve this puzzle easily using logic and strategic thinking. The Python interpreter, however, must take the brute-force approach of calculating everything from scratch. This nicely demonstrates your role as a computer programmer. You are the leading hand with unlimited power at your fingertips. But you must use your power wisely because the computer will do exactly what you ask him to do.
Are you a master coder?
Test your skills now!
Related Video
Solution
True | https://blog.finxter.com/daily-python-puzzle-fibonacci-series-2/ | CC-MAIN-2020-50 | refinedweb | 277 | 64.91 |
Forum:Proposal:The complete rules
From Uncyclopedia, the content-free encyclopedia
Here is my proposal for The Complete Rules of Uncyclopedia:
- Rule 1: Be funny and not just stupid. Rule 2: don't be a dick.
- Write good, funny stuff. At least amusing. Humour is very subjective, but if you're really clueless about it you'll learn quickly by cattleprod.
- To delete crap, mark stuff with {{NRV}} (where it has a week to live) or list it on QVFD (if it should die right now). Only send it to VFD if it's really marginal, and even then fix it instead if you think you can.
- The admins' job is to keep the site not shit.
- Admins zap the truly crappy on sight and NRV the eminently deletable that needs to explain itself fast. If you are sure your work was genius, (1) ask the admin why they zapped it (errors happen and are reversible) and (2) make it better.
- There are various procedural rules set out on some voting pages. They were each put there to keep the site not shit. If you have a serious argument that they keep you from being funny and not just stupid, discuss it rather than messing with them.
-.
- Admins sometimes get hotheaded because they deal with more stupid shit than you ever thought existed. Please forgive their flawed humanity.
- "Don't be a dick" is second to "Be funny and not just stupid", but it's not third to anything else. And if you do want to get away with being a dick, you'd better prove frequently you're the funniest bastard on the wiki.
That's how I see it. As far as I can tell, it all follows from that lot.
Is there anything important I've left out there? Is there anything too redundant in the above that could be cut?
What makes the above short is that it is fundamentally aimed at the clueful. In my experience, instruction creep happens when you try to explain clues to the clueless. That's why WP has so much policy it's routinely ignored. That and it attracts borderline aspergics like moths to a flame - David Gerard 03:08, 4 February 2006 (UTC)
- But part of the reason we feel we need to explain to the cluless is that they bitch and whine, and we sometimes look like assholes for simply banning them. If we set an official policy which states that it's ok to ban people for being clueless, I'll be good with showing them the door. Then we can trim down on the rules, and streamline everything. But I think that there needs to be a discussion as to the magnitude of cluefullness someone needs in order to participate on this site.
- More clearly stated: If we can blanket-ban anyone not cluefull enough to follow the simple rules, we can have simple rules. If we're expected to try and coach the clueless along, and show them The Uncyclopedia Way, we're not going to be able to have simple rules. Simple rules will help us cut down on the signal-to-noise ratio. However, kicking all the clueless out will help tremendously. And I really think they rely on each other. I'm hoping that it's not any surprise that I vote for simple rules. ;)
Sir Famine, Gun ♣ Petition » 14:38, 4 February 2006 (UTC)
- Ugh, not enough coffee. To make sure my point is clear, the reson for lots of words is that the clueless are...clueless. They raise a big stink when admins do their jobs, and delete/revert their crap. It's far easier to say "Read HTBFANJS" then just argue with the clueless. They don't understand what the admin's jobs are. They don't understand why their 3-line article got deleted. If we have simple rules, (like we once did), we end up spending a lot of time explaining to the clueless. If we have massive, detailed rules, we just point them there, and save our time for more important things, like deleting the crap they just posted, instead of reading the rules.
- Regardless of whether the rules are short and sweet or long and detailed, the cluless won't get them. If they are detailed enough to spell out what the cluless have done wrong, we can at least point them there in the hopes they get it. If they are short and sweet, we either ignore their whining and look like uncaring, distant pricks, or we waste a lot of our time explaining our actions.
Sir Famine, Gun ♣ Petition » 14:47, 4 February 2006 (UTC)
- Bah, tell them rules 1 and 2, then refer them to HowTo:Get Banned if they have any further questions. <<
>>16:21, 4 February 2006 (UTC)
- Despite the fact that we've been fairly free-form about it in the past, I would like it if we could set up some real rules as regard copyright. Creating a derivative work from a factual source to add funny should be fine. Photoshopping copyrighted images to add funny should be fine. Copying other people's jokes/comedy should be unacceptable unless they are public domain. Posting other people's images without modifying them yourself should be unacceptable unless they are public domain. --Sir gwax (talk)
17:01, 4 February 2006 (UTC)
- You're still trying to solve cluelessness with words. When I say this doesn't work, I'm speaking from bitter experience on Wikipedia. What actually happens is that if there are only a few words, the clueless assume it's a cabal conspiracy; if there's lots of words, they quibble and become querulous and rules-lawyer and try to rewrite them and generally make COMPLETE FUCKING PAINS IN THE ARSE of themselves. Then you eventually have to ban them for a year. Then because they're clueless they keep trying to come back, then you spot them because they're being clueless fuckheads in the exact same way, then you kick them off, then they assume conspiracy. Lots of words means so many rules that the clueful just ignore them, and more stuff for the clueless not to understand - David Gerard 01:04, 5 February 2006 (UTC)
- Nah, the one block rule above is:. If they're too clueless or obtuse to understand that repeat page blanking is bad, that vandalism is bad, that long shitty flamewarring is bad, etc., etc., we probably don't want them. Is that any clearer? For both the newbie and the admin - David Gerard 12:34, 5 February 2006 (UTC)
- I mulled this over, and I have to say, I think it has promise. I too have been a little irritated by our rules creep, even though I helped author some of it. Pointing people to a streamlined guide, and basing bans on those two guidelines might make life easier for all involved. I threw together a test page with a few more words than you have above. My one concern is that we'll have to be very viligant at keeping it simple.
- And I think I'm finally starting to get your whole point - adding "Don't be a Dick" as Rule #2 pretty much fixes any problems people might have with Rule #1. Because if they have an issue and are civil about it, all is well. If they have an issue and are a dick about it, the door hits their ass on the way out. I throw my full weight behind this plan of action. For.
Sir Famine, Gun ♣ Petition » 15:08, 5 February 2006 (UTC)
- I like it. Could probably do with shortening. But yeah, everything above after the first line is essentially commentary and hence endlessly malleable or dispensible - David Gerard 16:27, 5 February 2006 (UTC)
- Both of you are banned for lack of reading comprehension - that's my formatting - those are David Gerard's suggested rules. Please check the top of this section again. While I'm all for glory and honor, you at least need to try to get it right...
Sir Famine, Gun ♣ Petition » 03:04, 6 February 2006 (UTC)
- You, sir, are banned for inability to read in between the lines. User:Famine/Rules --> "the Famine rules." Also, your version is a bit more explicit. So I'm for the bastard child of David Gerard and Famine, if that makes it any clearer. --KATIE!! 03:16, 6 February 2006 (UTC)
- I far from rule - that was just me running with a modest proposal - nothing to shout about. (or butcher children over.) Anyway, this kid's got my good looks and his smarts, so what's not to like? Besides the fact that he can't inherit the kingdom until he kills off all the other heirs.
Sir Famine, Gun ♣ Petition » 03:28, 6 February 2006 (UTC)
I think we need to be a bit more specific on some things. While the obvious, such as page blanking and whatnot, doesn't need clarification, I can think of some questionable bans in the past. I tried to remove a reference to me on a particular article, got banned for a few days. How was I to know I couldn't try to keep attacks on users out of the main namespace? Another time Famine reverted a LOT of edits to Tourette's Syndrome with no reason mentioned in the edit summary. Spelling was wrecked, templates were altered, links removed, etc. When I reverted it asking what happened in the edit summary, it was reverted again with no answer. I reverted once more, mentioning in detail what is in the edit summary, got banned. Asked what was going on on Famine's talk page, got yelled at and ban extended. I particularly wonder about the rule with admins fallibility, since some admins seem unwilling to even admit their infallibility and ban those who question them. --User:Nintendorulez 18:57, 20 April 2006 (UTC)
- I believe that's adequately covered under the "questionable shit" clause. Also, in the future, it would behoove you to talk with the admin in question prior to reverting their edits, as that's a super-express route to bannination. --Algorithm (talk) 21:27, 20 April 2006 (UTC)
- Which isn't very specific to say in the rules Humorous? Yes. A legitimate rule? No. It's basically the same as "If we feel like banning you for no reason whatsoever when you least see it coming, we'll do it". My point is that we need clarification. The rules leave too much gray area of what is and isn't bannable, and I'm sure some people may constantly fear getting banned out of the blue for something that nobody ever knew was bannable. --User:Nintendorulez 22:03, 23 April 2006 (UTC)
There is a de-facto double standard; if someone like Nintendorulez were the one creating and recreating a substub like euroipods, he'd be banninated in a New York minute for recreating a twice-deleted page. I doubt that we really want to entrench this disparity (where some just get away with more than others) as "official" policy? --Carlb 01:17, 22 April 2006 (UTC)
- That was my whole point about Euroipods from the very beginning. All it does is encourage idiots to keep writing shit like that, and unlike the writers of Euroipods, they'll just wind up getting banned for it. But how were they to know that a featured article is also the kind of thing you get banned for? It's nothing but mixed messages. --User:Nintendorulez 22:03, 23 April 2006 (UTC) | http://uncyclopedia.wikia.com/wiki/Forum:Proposal:The_complete_rules | CC-MAIN-2014-10 | refinedweb | 1,950 | 70.63 |
# Thanks, Mario, but the code needs fixing — checking TheXTech
It's cool when enthusiastic developers create a working clone of a famous game. It's even cooler when people are ready to continue the development of such projects! In this article, we check TheXTech with PVS-Studio. TheXTech is an open implementation of the game from the Super Mario universe.
About the project
-----------------
[TheXTech](https://github.com/Wohlstand/TheXTech) is the SMBX 1.3. game engine rewritten on C++. The original [SMBX](https://github.com/smbx/smbx-legacy-source) (Super Mario Bros. X) was written on Visual Basic 6 by Andrew Spinks in 2009. It allows to create levels from the elements of the Nintendo's Super Mario Bros games. TheXTech accurately reproduces the original game's behavior. It also includes optional bug fixes. It runs not only on Windows, but also on macOS, and Linux systems with x86, ARM or PowerPC processors. Some developers also ported it on 3DS and PS Vista
The TheXTech developer — Vitaliy Novichkov (Wohlstand) — described the development process in detail on [Habr](https://habr.com/en/post/582566/). He also described the techniques he used to smooth out the differences when porting the project from VB6 to C++. There's a [disclaimer](https://github.com/Wohlstand/TheXTech/blob/d07a7ce1c9582084cf118d185f41a1eafef9e4cd/README.md) on the GitHub page that explains why the source code is not in the best condition. It's because the original code is unstructured something fierce. Its fragments you'll see below.
Results of the check
--------------------
### Cleaning the code
**Fragment one**
Can you see the error the analyzer found below?
[V547](https://pvs-studio.com/en/w/v547/) Expression 'NPC[A].Type == 54 && NPC[A].Type == 15' is always false. Probably the '||' operator should be used here. thextech npc\_update.cpp 1277
Of course not :) The error hides in the middle of the condition in string that has a 1400 character long. You have to scroll 5 screens to the right to find it. Let's format the code:
```
else if(
NPC[A].Type == 21 || NPC[A].Type == 22 || NPC[A].Type == 25
|| NPC[A].Type == 26 || NPC[A].Type == 31 || NPC[A].Type == 32
|| NPC[A].Type == 238 || NPC[A].Type == 239 || NPC[A].Type == 35
|| NPC[A].Type == 191 || NPC[A].Type == 193
|| (NPC[A].Type == 40 && NPC[A].Projectile == true) || NPC[A].Type == 49
|| NPC[A].Type == 58 || NPC[A].Type == 67 || NPC[A].Type == 68
|| NPC[A].Type == 69 || NPC[A].Type == 70
|| (NPCIsVeggie[NPC[A].Type] && NPC[A].Projectile == false)
|| (NPC[A].Type == 29 && NPC[A].Projectile == true)
|| (NPC[A].Projectile == true
&& (NPC[A].Type == 54 && NPC[A].Type == 15)) // <=
|| .... )
{ .... }
```
Now you can see it. *The NPC[A].Type*variable cannot be equal to two different values at the same time. Apparently, the condition was intended to be true for projectiles of types 54 and 15. However, now this part of the condition is always false. The developer should have changed the *AND* logical operator to the *OR* logical operator. Another option is to delete this part of the expression.
A couple of error examples in too long lines:
* [V501](https://pvs-studio.com/en/w/v501/) There are identical sub-expressions 'NPC[A].Type == 193' to the left and to the right of the '||' operator. thextech npc\_update.cpp 996
* V501 There are identical sub-expressions 'NPC[A].Type == 193' to the left and to the right of the '||' operator. thextech npc\_update.cpp 1033
* V501 There are identical sub-expressions 'NPC[A].Type != 191' to the left and to the right of the '&&' operator. thextech npc\_update.cpp 2869
* [V547](https://pvs-studio.com/en/w/v547/) Expression 'NPC[A].Type == 54 && NPC[A].Type == 15' is always false. Probably the '||' operator should be used here. thextech npc\_update.cpp 1277
**Fragment two**
The next code fragment was formatted for reading. Despite the greater chance of noticing errors here, someone missed them. Even 4 of them:
* [V501](https://pvs-studio.com/en/w/v501/) There are identical sub-expressions 'n.Type == 159' to the left and to the right of the '||' operator. thextech menu\_loop.cpp 324
* V501 There are identical sub-expressions 'n.Type == 160' to the left and to the right of the '||' operator. thextech menu\_loop.cpp 324
* V501 There are identical sub-expressions 'n.Type == 164' to the left and to the right of the '||' operator. thextech menu\_loop.cpp 324
* V501 There are identical sub-expressions 'n.Type == 197' to the left and to the right of the '||' operator. thextech menu\_loop.cpp 324
There is no point in double checking the same values here. Unnecessary comparisons can be removed.
No screenshots needed further.
**Fragment three**
[V501](https://pvs-studio.com/en/w/v501/) There are identical sub-expressions '(evt.AutoSection) >= (0)' to the left and to the right of the '&&' operator. thextech layers.cpp 568
```
#define IF_INRANGE(x, l, r) ((x) >= (l) && (x) <= (r))
else if( IF_INRANGE(evt.AutoSection, 0, maxSections)
&& IF_INRANGE(evt.AutoSection, 0, maxEvents))
{
// Buggy behavior, see https://github.com/Wohlstand/TheXTech/issues/44
AutoX[evt.AutoSection] = Events[evt.AutoSection].AutoX;
AutoY[evt.AutoSection] = Events[evt.AutoSection].AutoY;
}
```
In this code fragment the analyzer was confused by the duplication of expressions. This duplication appeared as a result of the macro expansion:
```
((evt.AutoSection) >= (0) && (evt.AutoSection) <= (maxSections)) &&
((evt.AutoSection) >= (0) && (evt.AutoSection) <= (maxEvents))
```
Such warnings can be suppressed. The developer can also rewrite the condition like this:
```
IF_INRANGE(evt.AutoSection, 0, min(maxSections, maxEvents))
```
This string also triggered the V590 rule.
[V590](https://pvs-studio.com/en/w/v590/) Consider inspecting this expression. The expression is excessive or contains a misprint. thextech layers.cpp 568
If we fix those warnings, it won't fix any bugs. The compilers delete unnecessary constructions anyway. However, we can clean up the code this way.
By the way, you can find an interesting moment, in this code fragment. Just follow the link from the code fragment's comment and look at the [issue](https://github.com/Wohlstand/TheXTech/issues/44). A user named ds-sloth suggested the following fix — to change this line:
```
AutoX[Events[A].AutoSection] = Events[Events[A].AutoSection].AutoX;
```
into this:
```
AutoX[Events[A].AutoSection] = Events[A].AutoX;
```
This change would fix the auto-scroll mechanism that is controlled by in-game events:
However, this fix is disabled by default because it changes or breaks the game behavior:
> **Wohlstand**: I guess the fix of this bug doesn't break levels that intended to work it, but breaks level that contains an absolutely invalid data and didn't intended to auto-scroll at all (knowing it was broken), in the result the issue #65. I guess since the 38A's per-section auto-scroll setup was utilized, when I will implement the way at PGE Editor to set them, I'll set this autoscrolling compat.ini value into 'false' by default.
>
>
>
> **Wohlstand**: Okay, I had to set the auto-scroll fix into 'false', mainly because there are several faulty levels that kept bad auto-scroll data after unsuccess experiments done by users, they making much more pain than proper use of this thing.
Therefore, in some cases, fixing the error requires consideration — fixing some of them may break the [bug compatability](https://en.wikipedia.org/wiki/Bug_compatibility) :). The following examples show such cases.
**Fragment four**
[V501](https://pvs-studio.com/en/w/v501/) There are identical sub-expressions to the left and to the right of the '!=' operator: NPC[A].Projectile != NPC[A].Projectile thextech npc\_hit.cpp 2105
```
else if ( NPC[A].Location.SpeedX != oldNPC.Location.SpeedX
|| NPC[A].Location.SpeedY != oldNPC.Location.SpeedY
|| NPC[A].Projectile != NPC[A].Projectile // <=
|| NPC[A].Killed != oldNPC.Killed
|| NPC[A].Type != oldNPC.Type
|| NPC[A].Inert != oldNPC.Inert)
{ .... }
```
This code fragment compares a set of data members in the *NPC[A]* and *oldNPC* objects. In the middle of this fragment the *Projectile* members of *NPC[A]* is compared with itself. Looks like a sloppy copypaste. Classic. However, only testing (or a full understanding of the game's logic) shows what would happen after we fix this condition. Maybe there's just an redundant check.
Similar error:
* V501 There are identical sub-expressions to the left and to the right of the '!=' operator: NPC[A].Projectile != NPC[A].Projectile thextech npc\_hit.cpp 2129
**Fragment five**
The last V501 error for today:
[V501](https://pvs-studio.com/en/w/v501/) There are identical sub-expressions 'MenuMode == MENU\_SELECT\_SLOT\_1P\_DELETE' to the left and to the right of the '||' operator. thextech menu\_main.cpp 1004
```
// Delete gamesave
else if( MenuMode == MENU_SELECT_SLOT_1P_DELETE
|| MenuMode == MENU_SELECT_SLOT_1P_DELETE)
{
if(MenuMouseMove)
s_handleMouseMove(2, 300, 350, 300, 30);
....
```
It's unclear whether only the first player should have the right to delete the save slot. In this case, the additional check for MENU\_SELECT\_SLOT\_1P\_DELETE is unnecessary here. Nevertheless, the code has the MENU\_SELECT\_SLOT\_2P\_DELETE constant. Probably, this constant should have been used in the right part of the expression.
This condition block has the same warning just below:
* V501 There are identical sub-expressions 'MenuMode == MENU\_SELECT\_SLOT\_1P\_DELETE' to the left and to the right of the '||' operator. thextech menu\_main.cpp 1004
### Problems with conditional operators
**Fragment six**
[V517](https://pvs-studio.com/en/w/v517/) The use of 'if (A) {...} else if (A) {...}' pattern was detected. There is a probability of logical error presence. Check lines: 1561, 1570. thextech player\_update.cpp 1561
```
if(Player[A].Character == 2) // luigi doesn't fly as long as mario
Player[A].FlyCount = 300; // Length of flight time
else if(Player[A].Character == 3) // special handling for peach
{
Player[A].FlyCount = 0;
Player[A].RunCount = 80;
Player[A].CanFly2 = false;
Player[A].Jump = 70;
Player[A].CanFloat = true;
Player[A].FlySparks = true;
}
else if(Player[A].Character == 3) // special handling for peach
Player[A].FlyCount = 280; // Length of flight time
else
Player[A].FlyCount = 320; // Length of flight time
```
In this fragment, several *else-if* constructs with the same condition (*Player[A].Character == 3*) do subsequent checks. This leads to the unreachable code in the second *else-if* construct. Looks like this code fragment prevents Princess Peach from flying in some places. We can try to remove the extra branch and simply assign 280 to the *Player[A].FlyCount* variable.
**Fragment seven**
The analyzer has detected suspicious code duplication in the *then* and *else* branches of condition:
[V523](https://pvs-studio.com/en/w/v523/) The 'then' statement is equivalent to the 'else' statement. thextech npc\_hit.cpp 1546
```
if(NPC[C].Projectile && !(NPC[C].Type >= 117 && NPC[C].Type <= 120))
{
if(!(NPC[A].Type == 24 && NPC[C].Type == 13))
NPC[A].Killed = B;
else
NPC[A].Killed = B;
}
```
Maybe some special exception is broken where this function determines whether a projectile can kill a specific type of NPC.
**Fragment eight**
The analyzer has detected an impossible condition:
[V547](https://pvs-studio.com/en/w/v547/) Expression 'A == 48' is always false. thextech effect.cpp 1652
```
else if(A == 16) // Dead Giant Bullet Bill
{
numEffects++;
Effect[numEffects].Shadow = Shadow;
....
Effect[numEffects].Location.SpeedY = Location.SpeedY;
Effect[numEffects].Location.SpeedX = Location.SpeedX;
if(A == 48) // <=
Effect[numEffects].Location.SpeedY = -8;
Effect[numEffects].Life = 120;
Effect[numEffects].Type = A;
}
```
Since the program can enter this block only if the *A* variable equals 16, the *A == 48* condition is never fulfilled. As a result the effect will have the wrong vertical velocity. So the Giant Bullet Bill's death will not be dramatic enough. :)
**Fragment nine**
Another example of a useless conditional operator:
[V547](https://pvs-studio.com/en/w/v547/) Expression 'tempPlayer == 0' is always true. thextech blocks.cpp 576
```
// don't spawn players from blocks anymore
tempPlayer = 0;
if(tempPlayer == 0) // Spawn the npc
{
numNPCs++; // create a new NPC
NPC[numNPCs].Active = true;
NPC[numNPCs].TimeLeft = 1000;
....
```
Apparently, after refactoring, the *tempPlayer* variable is always initialized to zero. We can reduce the code nesting by removing an unnecessary condition.
**Fragment ten**
Here is an extra check that the logical result of the comparison is not equal to 0:
[V562](https://pvs-studio.com/en/w/v562/) It's odd to compare a bool type value with a value of 0. thextech editor.cpp 102
```
if(!MagicHand)
{
if((getKeyState(vbKeyPageUp) == KEY_PRESSED) != 0) // <=
{
if(ScrollRelease == true)
....
```
We can write simply:
```
if(getKeyState(vbKeyPageUp) == KEY_PRESSED)
```
More of such warnings:
* V562 It's odd to compare a bool type value with a value of 0. thextech editor.cpp 115
* V562 It's odd to compare a bool type value with a value of 0. thextech editor.cpp 170
**Fragment eleven**
The following example may contain a logical error. The condition first checks the value of the array by the *whatPlayer* index. Only after that the fragment checks the *whatPlayer* variable's range:
[V781](https://pvs-studio.com/en/w/v781/) The value of the 'whatPlayer' index is checked after it was used. Perhaps there is a mistake in program logic. thextech blocks.cpp 159
```
if(b.ShakeY != 0 || b.ShakeY2 != 0 || b.ShakeY3 != 0)
{
if( b.RapidHit > 0
&& Player[whatPlayer].Character == 4 && whatPlayer > 0) // <=
{
b.RapidHit = (iRand() % 3) + 1;
}
return;
}
```
This may result in undefined behavior.
**Fragment twelve**
A bit weird fragment. After the developer commented the part of an expression, the variable began to assign itself the same value:
[V570](https://pvs-studio.com/en/w/v570/) The 'NPC[A].Location.X' variable is assigned to itself. thextech npc\_hit.cpp 1995
```
else
{
NPC[A].Location.Y = NPC[A].Location.Y + NPC[A].Location.Height;
NPC[A].Location.X = NPC[A].Location.X; // - (32 - .Location.Width) / 2
....
}
```
The program's behavior doesn't change from such expressions. However, this code fragment may indicate logical errors. For example, a logical error appears if, after debugging, the developer doesn't put the commented fragment back.
There are examples of unnecessary assignment:
* V570 The 'Player[A].MountOffsetY' variable is assigned to itself. thextech player.cpp 1861
* V570 The 'tempLocation.X' variable is assigned to itself. thextech npc\_update.cpp 4177
* V570 The 'tempLocation.Width' variable is assigned to itself. thextech npc\_update.cpp 4178
### Other errors
**Fragment thirteen**
A weird loop in a function that tries to read a JPEG image:
[V654](https://pvs-studio.com/en/w/v654/) The condition 'chunk\_size > 0' of loop is always true. thextech image\_size.cpp 211
```
static bool tryJPEG(SDL_RWops* file, uint32_t *w, uint32_t *h)
{
....
size_t chunk_size = 0;
....
do
{
SDL_memset(raw, 0, JPEG_BUFFER_SIZE);
pos = SDL_RWtell(file);
chunk_size = SDL_RWread(file, raw, 1, JPEG_BUFFER_SIZE);
if(chunk_size == 0)
break;
head = findJpegHead(raw, JPEG_BUFFER_SIZE);
if(head)
{
if(head + 20 >= raw + JPEG_BUFFER_SIZE)
{
SDL_RWseek(file, -20, RW_SEEK_CUR);
continue; /* re-scan this place */
}
if(SDL_memcmp(head, "\xFF\xE1", 2) == 0) /* EXIF, skip it!*/
{
const Sint64 curPos = pos + (head - raw);
Sint64 toSkip = BE16(head, 2); //-V629
SDL_RWseek(file, curPos + toSkip + 2, RW_SEEK_SET);
continue;
}
*h = BE16(head, 5);
*w = BE16(head, 7);
return true;
}
} while(chunk_size > 0); // <=
return false;
}
```
The *chunk\_size* variable is updated almost at the very beginning of the loop iteration. If the variable equals zero, the loop breaks. After that the variable goes to checking the exit condition of the loop. However, it is guaranteed to be greater than zero. Here we can use the infinite *while (true)* loop.
**Fragment fourteen**
This code fragment has the bitwise *OR* operator instead of the logical one. This operator is used between calls of functions that return *bool*. As a result, both functions are always executed, which is less effective:
[V792](https://pvs-studio.com/en/w/v792/) The 'vScreenCollision' function located to the right of the operator '|' will be called regardless of the value of the left operand. Perhaps, it is better to use '||'. thextech gfx\_update.cpp 1007
```
bool vScreenCollision(int A, const Location_t &Loc2)
....
// warp NPCs
if(Player[A].HoldingNPC > 0 && Player[A].Frame != 15)
{
if(( vScreenCollision(Z, NPC[Player[A].HoldingNPC].Location)
| vScreenCollision(Z, newLoc(....))) != 0 // <=
&& NPC[Player[A].HoldingNPC].Hidden == false)
{
....
```
The same error appears in other places:
* V792 The 'vScreenCollision' function located to the right of the operator '|' will be called regardless of the value of the left operand. Perhaps, it is better to use '||'. thextech gfx\_update.cpp 1253
* V792 The 'vScreenCollision' function located to the right of the operator '|' will be called regardless of the value of the left operand. Perhaps, it is better to use '||'. thextech gfx\_update.cpp 1351
* V792 The 'vScreenCollision' function located to the right of the operator '|' will be called regardless of the value of the left operand. Perhaps, it is better to use '||'. thextech gfx\_update.cpp 1405
* V792 The 'CheckCollision' function located to the right of the operator '|' will be called regardless of the value of the left operand. Perhaps, it is better to use '||'. thextech player.cpp 4172
**Fragment fifteen**
In the following example the developer constructs an unnecessary string, passing the result of calling the *c\_str()* member function. The developer passes it to the function which accepts a reference to *std::string*. The code is less efficient that way. When the developer converts *std::string* into *char\**, information about the current length of the string is lost. When subsequently constructing new *std::string*, the program has to recalculate the length by a linear search for terminal null character. The compiler doesn't optimize this moment — we checked it with [Clang](https://godbolt.org/z/E9Mq6197d) with -O3 optimizations.
[V811](https://pvs-studio.com/en/w/v811/) Decreased performance. Excessive type casting: string -> char \* -> string. Consider inspecting first argument of the function open\_file. thextech graphics\_funcs.cpp 63
```
bool FileMapper::open_file(const std::string& path)
{
return d->openFile(path);
}
FIBITMAP *GraphicsHelps::loadImage(std::string file, bool convertTo32bit)
{
....
if(!fileMap.open_file(file.c_str())) // <=
return nullptr;
....
}
```
**Fragment sixteen**
In this loop the length of the same strings is repeatedly calculated. The developer should declare it as constants of the *std::string* type and use the *size()* method:
[V814](https://pvs-studio.com/en/w/v814/) Decreased performance. The 'strlen' function was called multiple times inside the body of a loop. thextech menu\_main.cpp 1027
```
#define For(A, From, To) for(int A = From; A <= To; ++A)
if(MenuMouseMove)
{
For(A, 0, optionsMenuLength)
{
if(MenuMouseY >= 350 + A * 30 && MenuMouseY <= 366 + A * 30)
{
if(A == 0)
menuLen = 18 * std::strlen("player 1 controls") - 4; // <=
else if(A == 1)
menuLen = 18 * std::strlen("player 2 controls") - 4; // <=
....
```
This pattern is quite common:
* V814 Decreased performance. The 'strlen' function was called multiple times inside the body of a loop. thextech menu\_main.cpp 1029
* V814 Decreased performance. The 'strlen' function was called multiple times inside the body of a loop. thextech menu\_main.cpp 1034
* V814 Decreased performance. The 'strlen' function was called multiple times inside the body of a loop. thextech menu\_main.cpp 1036
* V814 Decreased performance. The 'strlen' function was called multiple times inside the body of a loop. thextech menu\_main.cpp 1040
* V814 Decreased performance. The 'strlen' function was called multiple times inside the body of a loop. thextech menu\_main.cpp 1131
* V814 Decreased performance. The 'strlen' function was called multiple times inside the body of a loop. thextech menu\_main.cpp 1174
* V814 Decreased performance. The 'strlen' function was called multiple times inside the body of a loop. thextech menu\_main.cpp 1200
* V814 Decreased performance. The 'strlen' function was called multiple times inside the body of a loop. thextech menu\_main.cpp 1204
Conclusion
----------
According to [Wikipedia (ru)](https://ru.wikipedia.org/wiki/Super_Mario_Bros._X), TheXTech was first publicly released just a month after the SMBX source code was published. It's really cool for a full cross-platform project porting to another language. Especially on C++.
Developers planning a major code revision can try PVS-Studio. We provide a [free](https://www.pvs-studio.com/en/open-source-license/) license for open source projects.
As a bonus — here's the Mario-themed video from our YouTube channel: | https://habr.com/ru/post/590657/ | null | null | 3,390 | 53.37 |
Hello, not sure if this has been discussed before, but I would like to say
a suggestion of something that could be added to swift's standard library.
Right now if you want to get a random number, you need to do it differently
depending on whether you're on macOS or linux (or do both). In linux you
would use the 'random()' function from 'Glibc', and in macOS you would use
the 'arc4random_uniform()' from 'Darwin'.
Given how common it is to want to get a random number, I feel like it would
be worthwhile to have a function in the standard library that deals with
these differences, so that you can just get a random number and not have to
worry about the different OS.
So basically, you would simply import 'Foundation', and then use a standard
'random()' function.
Even better if you also add some helper functions, like a get random
int/float with range parameters.
For example, a possible implementation could be:
import Foundation
// so we get different numbers every run
srandom(UInt32(NSDate().timeIntervalSince1970))
func getRandom(_ min: Int, _ max: Int) -> Int {
let diff = max - min + 1
#if os(Linux)
return min + Int(random() % diff)
#else
return min + Int(arc4random_uniform(UInt32(diff)))
#endif
}
print(getRandom(50, 100))
Just an idea, thanks for reading, cheers. | https://forums.swift.org/t/random-improvements/5573 | CC-MAIN-2018-51 | refinedweb | 219 | 53.95 |
Initialize the library.
#include <mm/md.h>
int mmmd_init( const char *config )
The path to the configuration of the library (may be NULL)
Initialize the library. You must call this function before any other libmd function to initialize the library before using it. This function loads any metadata providers (MDPs) listed in the configuration file into the library. The default path for the configuration file is /etc/mm/mm-md.conf.
The plugin entries in the configuration file must contain dll attributes that provide filenames that match the plugin names. All other plugin attributes are ignored by the library and may be used by the plugins during metadata extraction.
0 on success, -1 on error (errno is set) | http://www.qnx.com/developers/docs/6.6.0.update/com.qnx.doc.libmd/topic/api/mmmd_init.html | CC-MAIN-2018-47 | refinedweb | 118 | 57.27 |
There’s a problem that a coworker recently brought up. The problem statement can be found here.
This is a re-hash of an existing problem known as the one hundred prisoners problem. It seems impossible at first, and many naive approaches yield failing results. But, given the correct approach, it is solvable with a surprisingly high probability.
A Solution
It’s really just a permutation problem. The basic idea is that the boxes are numbered 1..100 and they all contain a bill with a number 1..100. To construct a working solution, you use the bills as pointers to box numbers in the following way. You start at the box labelled with your number, and go to the box number of the bill it contains. Keep doing that, looking in the box and going to the box of the bill you find inside. Eventually, you get to the box containing the bill that points to where you started – and that’s the bill you’re looking for. So, the question really becomes: How often does a random permutation of degree $n$ contain a cycle having length greater than $n/2$? If you get a longer cycle, then anyone with a number in that cycle is screwed because it takes them longer than $n/2$ steps to find their bill. If there are only cycles having lengths less than $n/2$, then everyone can find their bill in the appropriate number of steps.
So, how many random permutations of degree $n=100$ contain only cycles having length less than 50? For this, we can look at approximations given by Stirling numbers of the first kind. Essentially, the number of random permutations having only cycles of length less than $n/2$ (in our case 50) as asymptotic to $log(2)$, which is around 0.3010. That’s a bit surprising, because it means that the strategy above is expected to win roughly 30% of the time for large numbers of boxes.
Testing with Sage
How well does the strategy actually perform when $n=100$? We can test this out in Sage.
def max_length_orbit_random_perm(n): """ Generate a random permutation on 1..n and compute the longest orbit.""" return max([len(i) for i in Permutations(n).random_element().cycle_tuples()]) won = 0 tries = 10000 for i in range(tries): if max_length_orbit_random_perm(100) <= 50: won += 1 print "won %s out of %s" % (won, tries)
And we get the following.
won 3072 out of 10000
So, we win roughly 3 out of 10 times. If we were charged $1 to play the game, but won $100 if everyone found their dollar, then we’d be doing very well to play the game. | http://code.jasonbhill.com/sage/solving-the-impossible-bet/ | CC-MAIN-2019-43 | refinedweb | 447 | 72.56 |
Finance › Accounting ›
pv
Return the present value of an investment.Controller: CodeCogs
Contents
Interface
C++
Pv
This function calculates the present value, v_0, for a sequence of n future payouts p followed by a final payment v_n: If rate = 0,
Purchase a Licence for more information.The code also uses an enumerated type PaymentPoint, using the following values:
- pp_EndOfPeriod = 0
- pp_StartOfPeriod = 1.
Example 1
- A lady wins a 500,000 payments for 20 years. The cu rrent treasury bill rate of 6% is used as the discount rate.
#include <stdio.h> #include <codecogs/finance/accounting/pv.h> int main(int argc, char *argv[]) { double d = Finance::Accounting::pv(0.06, 20, 500000, 0, Finance::Accounts::pp_EndOfPeriod); printf("The present value of the $10 million prize is: %7.2f\n", d); return 0; }Output:
The present value of the $10 million prize is: 5734960.61
References
Parameters
Authors
- James Warren (May 2005)
Source Code
Source code is available when you agree to a GP Licence or buy a Commercial Licence.
Not a member, then Register with CodeCogs. Already a Member, then Login.
Last Modified: 8 Jul 08 @ 00:41 Page Rendered: 2022-03-14 17:53:23 | https://www.codecogs.com/library/finance/accounting/pv.php | CC-MAIN-2022-21 | refinedweb | 196 | 58.08 |
EasyVR
The EasyVR module by Veear and available from several other distributers is a small low-cost voice recognition module. Pricing is about the same as mbed. A basic speech recognition demo was working after about an hour of work after opening the box. The black potted IC in the middle is likely the processor chip and the large chip is flash. Most likely, it is one of the ICs from Sensory that was used in the recent reincarnation of Furby and quite a few other embedded devices and toys.
The EasyVR module, microphone, and cable set
Wiring
It outputs a serial TTL signal and runs off of 3.3V. Just plug in the microphone, hook up power, and then the serial RX/TX pins. Don't forget the RX and TX swap when connecting to mbed (i.e., RX-TX and TX-RX) and be very careful not to swap the color coded power pins!
Wire connections from EasyVR to mbed
Training using the EasyVR GUI
The serial bridge code below can then be run on mbed so that it can talk to their PC-based EasyVR GUI training program over mbed's USB Virtual Com Port. This software allows the user to create and test new speaker dependent (i.e., trained for one person) command words.
Bridge_for_EasyVR_GUI_tool
//EasyVR Bridge Program to connect to PC using mbed #include "mbed.h" Serial pc(USBTX, USBRX); // tx, rx Serial device(p13, p14); // tx, rx int main() { while(1) { if(pc.readable()) { device.putc(pc.getc()); } if(device.readable()) { pc.putc(device.getc()); } } }
Import programEasyVR_Bridge
Serial Bridge program to support using the EasyVR with mbed. It is run when using the PC-based EasyVR GUI tools for voice recognition training and testing.
The PC-based EasyVR GUI using the mbed bridge code for training
Standalone Voice Recognition
It comes with some built-in speaker independent voice recognition commands (available in English, Italian, Japanese, German, Spanish and French). Here is a demo based on the number commands. This video is using the set of number words (0..10) to control (toggle) the 4 leds on mbed. The demo needs some more work to add timeout and error code checking as suggested in their manual, but it works fairly well without it. Commands and responses are all sent as printable ASCII characters.
mbed using EasyVR to toggle LEDs
Speaker_Independent_VR_Demo
#include "mbed.h" DigitalOut led1(LED1); DigitalOut led2(LED2); DigitalOut led3(LED3); DigitalOut led4(LED4); Serial device(p13, p14); // tx, rx int main() { char rchar=0; //wake up device - needs more work and a timeout device.putc('b'); while (device.getc()!='o') { device.putc('b'); led1 = 1; wait(0.2); } led2=1; while (1) { device.putc('i'); //Start Recognition device.putc('D'); //Use Wordset 3 - the numbers 1..10 //Use built-in speaker independent numbers (0..10) and listen for a number while (device.readable()!=0) {} if (device.getc()=='s') { device.putc(' '); rchar=device.getc(); if (rchar=='B') led1=!led1; if (rchar=='C') led2=!led2; if (rchar=='D') led3=!led3; if (rchar=='E') led4=!led4; } } }
Speech Synthesis and Audio output
For speech synthesis, the EasyVR can play compressed audio files of human speech. The EasyVR can also output to a 8ohm speaker (J2 jack in upper right corner of board) for feedback and speech synthesis, but that feature was not used in the first demo. Users can make their own custom sound tables from *.wav files using Sensory's Quick Synthesis 5 tool included with the EasyVR software. I had issues running it on Win 7 64-bit and it could not seem to compress and save the sound files, but it worked OK on a different PC with a 32-bit OS. According to a recent EasyVR forum post a new version should be available soon that should fix this issue. There is also a fix for 64-bit Windows posted in the forum that helps with some of the sound table build issues. Audio files must be in *.wav format at 22050 Hz with 1 channel and 16-bits. Audacity, a free open source digital audio edit tool, can be used to convert most audio files to this format so that they can be used in the Quick Synthesis tool. The EasyVR GUI includes the commands to process and download the custom sound tables produced by Quick Synthesis to the EasyVR module. Whenever building a new sound table, build it, save it, and rebuild it. This is required to update all of the time stamps in the project so that the EasyVR GUI tool will allow downloading the new sound table.
The Quick Synthesis tool is used to generate compressed sound files
The tool to download new sound tables in the EasyVR GUI operates at 115200 baud, so to download a new sound table to the module's flash, a serial bridge program is needed setup for 115200 baud instead of the 9600 baud rate used earlier for speech recognition commands. A pull-up resistor must be attached to the /XM pin to force it >3V (100ohm for 3.3v supply or 680ohm for a 5V supply) and power must be cycled after the pull-up is in place. Here is the bridge code to download new sound tables:
Import programEasyVR_SoundTableBridge
EasyVR Bridge Program to connect to PC using mbed and download custom sound tables at 115200 baud
In the download dialog box, also check the "slow transfers" (115200 baud) box before hitting the final download button. After downloading the new sound table to flash, remove the jumper, cycle power, reload the 9600 baud bridge program, connect and click on the last sound table group in the left column. It should expand to show the new sounds just downloaded. You can select a new sound and click the speaker icon to play it on the speaker attached to the EasyVR module. I seemed to get a bit more volume on the speaker using a 5V supply for the EasyVR. This process is documented in the newest version of the EasyVR documentation from Veear. There is also a programming and firmware update cable that might make the process easier that should be introduced soon.
A similar setup can be used for firmware updates (pullup and 115200 baud). I had an early? EasyVR module with version “A” firmware and updated it to version “B” firmware based on instructions found at the EasyVR forum. Version “A” does not support sound output and it does not have the built-in beep sound table. Note: The older VRbot modules cannot be upgraded. The module type is printed on the PCB silkscreen.
Using the EasyVR GUI download tool to program new sound files to flash at 115200 baud
The new sound table should appear back in the EasyVR GUI at 9600 baud
Once the sound table is in flash on the EasyVR module, it can be played back on the speaker with a play command using the index into the sound table as shown in the GUI image above. A small delay is needed between characters in complex multicharacter commands to ensure that a character is not occasionally dropped in the EasyVR UART. This delay is provided by using wait(.001). The EasyVR responds with a "o" after the sound is played back. A C function for playback is shown below. Num is the index into the sound table.
function_to_play_sound
// Function to play a sound file on speaker void speak(int num) { // Send Play Sound command device.putc('w'); // small delay is needed between characters wait(.001); // Sound table index device.putc('A' + num/32); wait(.001); device.putc('A' + num%32); wait(.001); // max volume device.putc('P'); // Wait for response of 'o' as playback ends while (device.getc()!='o') {} wait(.25); }
Using Speech Synthesis with Speech Recognition
For the second demo which took a bit more work, several appropriate computer voice response *.wav files were obtained on the web. Using Audacity, the *.wav files were converted to the correct sample rate for use in the Quick Synthesis tool. In Quick Synthesis, the audio files were compressed to a low data rate. The default compression technique was used and there are also quite a few others to select from with different size and quality trade offs. Then using the EasyVR GUI tool download option, the new sound table with the compressed audio files was programmed into the EasyVR flash memory.
For a more advanced demo, code was written to use speech synthesis output for vocal user prompts, SI (speaker independent) recognition for the LEDs, and a new SD (speaker dependent) word, mbed, for use as a password. In the EasyVR GUI, the train option was used to add the new SD word, mbed.
Mbed EasyVR Speech Synthesis and Recognition Demo
This second demo shows the EasyVR doing both speech synthesis and speech recognition. Speech synthesis plays compressed *.wav files from its flash memory on an 8 ohm speaker. Speech recognition includes a new speaker dependent word, mbed, that is based on a training sample from the user, and the built-in speaker independent numbers (0...10) that will work with any speaker without training. In the video, after logging on with the password of “mbed”, it prompts for a command code number. The numbers 1…4 will toggle the four built-in LEDs on mbed. Note that when an invalid number is spoken (i.e., not 0...10) it prompts the user to “restate the command”. Each successful recognition is “acknowledged”.
Import programEasyVR_SRSSDemo
EasyVR Speech Recogniton and Speech Synthesis Demo
To run the demo, you will also need to download the new sound table project to flash, and add and then train the password (mbed) in Group 1 using the EasyVR GUI. A zip file of the sound table project is available here
Ideas for Further work
Keep in mind that noise, distance from the microphone, and variations in the way words are spoken will all impact the accuracy of any speech recognition system. There is even a variation in the way an individual speaker says the same word from day to day.
Users can develop speaker dependent (i.e., trained for one speaker based on samples) recognition words with the EasyVR GUI tool that comes with the EasyVR module. For users that want to develop their own custom speaker independent (i.e., works for any speaker) recognition words, additional software is needed from Sensory (Quick T2SI) that does not come with the module. The larger and more expensive VoiceGP DK-T2SI board comes with this additional software.
There are some open source text-to-speech synthesis tools such as Espeak that produce computer generated speech, and the speech output can be saved as *.wav files, but they require a fairly large amount of memory and some file space. They could be used to generate a computer sounding voice for the EasyVR module offline by saving the *.wav files, if you did not want to use human speech. Recorded human speech is typically easier to understand. There are also several open source speech recognition programs available for embedded devices such as PocketSphinx.
The password group in the EasyVR tool uses SV (speaker verification) and requires a more precise match. It must be trained under similar conditions (environment noise and distance from microphone). Speaker verification technology uses word-spotting techniques to dramatically enhance password biometric accuracy in noisy environments
Another interesting project would be to use the EasyVR for voice control of a robot such as the Roomba or iCreate. It has a built-in speaker independent vocabulary for robot movement, and this is the one of the primary target markets for the device.
The 2005 Furby with a Sensory VR IC
In case you missed them, this video of a 2005 Furby II shows the toy's built-in speech recognition and synthesis capabilites. The software from Sensory can also keep track of when the mouth should move (called lipsync in the tool).
Similar software is available from Sensory for ARM cores and can be licensed for use in commercial products.
Recent demo of Sensory Software on a phone with a GPS application
Toy dog, Talking Clock, and Bluetooth headset demo
14 comments on EasyVR:
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This looks like it could be a lot of fun - good find Jim! | https://os.mbed.com/users/4180_1/notebook/easyvr/ | CC-MAIN-2018-39 | refinedweb | 2,056 | 71.95 |
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10/31/2014
151
9781921523090
Visual Basic 100 Success Secrets
Visual Basic 100 Success Secrets VB 100 Most Asked Questions: The Missing Visual Basic Reference Guide
is intended to convey endorsement or other affiliation with this book. or otherwise. No such use. mechanical. Where those designations appear in this book. without the prior written permission of the publisher. Trademarks Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. or the use of any trade name. Notice of Liability The information in this book is distributed on an “As Is” basis without warranty. the designations appear as requested by the owner of the trademark. recording..Visual Basic 100 Success Secrets Copyright © 2008 Notice of rights All rights reserved. and the publisher was aware of a trademark claim. electronic. photocopying. All other product names and services identified throughout this book are used in editorial fashion only and for the benefit of such companies with no intention of infringement of the trademark. . No part of this book may be reproduced or transmitted in any form by any means.
This book is also not about Visual Basic’s best practice and standards details. it introduces everything you want to know to be successful with Visual Basic. Instead. Instead. It tells you exactly how to deal with those questions.Visual Basic 100 Success Secrets There has never been a Visual Basic Guide like this. 100 Success Secrets is not about the ins and outs of Visual Basic. our consultancy and education programs. it answers the top 100 questions that we are asked and those we come across in forums. with tips that have never before been offered in print. .
.................................36 ...............................26 Two Ways to Overcome VB Net Print Function Difficulty .........Net Combobox...........19 What is the VB Net Using Statement .............23 Wise Moves with Visual Net and Excel....14 VB Net List: Separating Different Program Instances ...................................................................25 How to Make VB Net Listbox Easy to Control......................Table of Contents Managing VB Net Code for Accounting and POS ...............24 The Importance of the VB Net Format..........13 Parts of the VB Net For Each Syntax .32 VB Runtime: Allowing Visual Basic to Run on Workstations.10 VB net Database is the Way to Go .................21 Stuck in a Rut? VB Net Datagrid is Your Best Choice ............................................................................20 A Detailed Discussion on Vb .........29 VB Net XML: Making Databases Easier to Access......................................22 Terminology You Ought to Know in Vb Net Dataset ..................................34 How Does a VB Select Statement Operates?.............................................................12 Why You Should Consider a Vb Net Download....................................................28 VB Net SQL: Adding Database to the Programming Language..31 VB Programming: Creating an Easy Environment for New Program Developers...............................15 VB Net Listview: Creating Easy to Control Graphical Interface17 How to Troubleshoot VB Net Service Application Time Out ...11 How Programmers Make Use of Vb Net Data Grid View...................
. 60 Where to Get Visual Basic Help to Solve Program Issues?.............................................................................................................................. 47 How to Initialize the VB Replace Function . 62 What are Arrays in Visual Basic?............................................................................................ 63 Excel Application within the Visual Basic Program . 40 Visual Basic Database: Using Third Party Applications for Effective Interface............................... 38 Visual Basic Access Automation: Overview of VB Automation with Access Program ..................... 54 Visual Basic 2005 Express: A Good Platform to Learn Basic Programming ..... 67 ...................................................................... 42 Getting to Know Visual Basic for Applications ....................................................................................Where to Find Free VB Source Code ............................................................................... 58 The Cool Features of Visual Basic Express Edition................................. 65 Things You Should Know about Visual Basic ........ 52 Parts of the VB Split Operations ........................... 53 How VB Tutorials Help New Programmers? ............... 45 Visual Basic Runtime: First Things First...................... 61 Why it is Better to Get into Visual Basic Programming ................................. 46 The Advantages of Using VB Print Applications................................................... 49 An Overview of the Functionalities of VB Scripts.................... 44 The Great Facets of Visual Basic Program............ 56 The Importance of Creating Visual Basic Array......................... 37 How to Ensure Stable VB Timer Coding System ............................. 51 What are the Uses of VB Source Codes? ........
.............................NET and its Characteristics .............................................80 VB Database: Training through Database Projects ......82 VB Excel: Automatic is better than Manual ........................68 How VB6 Arrays Differ from VB...........................................................................97 Exploring VB Net Express ........93 What are Arrays in VB?.......................................................................................91 VB Loop: True or False/Execute and Terminate.............................95 Choosing in Between C and VB ..............99 Dissecting the VB Scripting ..................101 ................................................................88 VB Date: From 1...................................................0..............................................................................90 VB for: Automated Applications ..100 How to Handle VB Strings Effectively .........NET Arrays .................................84 VB Instr: Finding the String? ..............................................................................................................................98 Understanding the Strings in VB Net ....73 The VB...87 VB Code: Improved Form of the HTML....................................................................................................................................................................................71 Learning Visual Basics For Free................................................96 Manipulating DataTable Function in VB Net .........78 VB Access: For the Queries to the Questions ........75 Visual Basic and its Features ........What Visual Basic Listbox Can Do? ...............0 to 6...................................................................................72 What Is a VB Array? ....69 How to Get Visual Basic Download and Updates ................77 Microsoft Visual Basic: Programming is Easier....................................86 VB 2005: From Books to Incentives ................
... 112 Visual Basic 2005 and its Evolution.................. 132 ................................................... 125 VB Function: Essential as a Business Language ............................................................................................... 103 Understanding the Dominion of Visual Basic Net........... 105 How are C# and VB Different and Similar?........... 116 Reinforcing kids’ visual interest and skills through VB Express tutorial course ..................................... 111 Visual Basic 6: What is it?.... 107 Working on the Method called VB Net Date ........ 106 How Effective and Efficient VB Net ArrayLists are? ....... 128 Visual Basic: What You Need to Know about VB Net Class ..................... 108 A Method Called VB Net Split ................................................................. 117 Understanding the concept of VB class ........................Learning the Simplicity of Visual Basic 6...................... 110 VB SQL and its underlying prowess .. 121 VB COM: Define......................................................................0 ........ 102 Visual Basic Codes: How to Better Understand Them .......................................... 114 The Jeopardy of a Worm VB..................................................................................................... 109 VB Net Thread: A Good Source of Information and Updates... 123 Making the most of VB Selec Case statements... 130 The ABC’s of Visual Basic........ VB Functions & VB Applications ........................... 113 Visual Basic Express: Learning it fast and easy .................. 119 What is a VB format? ............................... 127 One of the Best Applications of Visual Basic: VB Games.......................................................................................
......142 The Transition to ...............137 The Basics of Microsoft Visual Basic (VB) .................NET ............What is the Main Difference between Visual Basic’s VB.................148 ................................Net and VB......................134 The Need to Download and Upgrade to VB......138 Understanding Microsoft Visual Basic 2005 .................NET Framework from VB 6 .........................133 The Ease of Converting C# to VB...........147 Learning VB Arrays .................................135 Visual Basic Tutorials for Free ..................................................................................................................145 Using Windows API in Visual Basic (VB) ..............................................0 to VB 6..140 The Need to Upgrade Software Applications from Microsoft Visual Basic 6................0 to ..........144 From VB 1....................................NET....0 – The Visual Basic Software Evolution...........................Net C#?.....NET................
9 .
Ever since the VS2005. There are also other source codes of visual basic which can be used for POS and accounting software. It is only through research and development where you can get great projects that are related to database in order to succeed in the shortest time while delivering high quality outputs as well. This is because using this will enable you to have great support in order to access as well as process data in a frequent manner. In addition. the developer. visual basic works really well using the . This also means a lot of work falls into the laps of developers should the source code happen to be unable to support the programming of rapid application development. which is also free for users of desktop applications and other users of small business software. you have no other way to turn to but to VB net code. there are now a lot of great rapid application development tools which help you.net framework. With VS2005 comes the SQL server 2005. it is nonetheless remarkable to see how technology in the area of visual basic has risen from a once simplistic mode into something that is beyond the scalability of our goals and objectives. create good business software in very little time. . This SQL Server 2005 also plays an important part in order to ensure the scalability of both storage and software.10 Managing VB Net Code for Accounting and POS When it comes to looking for the most reliable base ground for your Accounting and POS software. an express edition software. While a lot of work is left to be done. but there are only a token few that can use rapid application development’s methodology and design.
You also have the option to design your software into something that involves a multiple platform format. Visual basic is the prime developer of both inventory and accounting software and is now slowly making the shift from Visual basic dot net in order to allow you users to make full use of the benefits that come with the dot net platform. Aside from this. So if you are still using VB 6 for all your database needs. then you really need to move on to this new and exciting platform.11 VB net Database is the Way to Go If you want a better way of taking stock of your company’s database. the best thing you can do is invest in visual basic. This year’s Visual studio 2008 is one that releases so many great technologies that include an N-Tier RAD and LINQ tool. you have a chance to distribute or even update your software in a much faster time. which is indeed a very useful tool. you also get wide access to a range of powerful third party tools. there are so many other equally great benefits that many developers cannot help but make the move. then? First. how can one resist the allure of a system that will allow you to design and deliver a project faster than any of your competitors. Of course. What are its implications on the developer of visual basic net inventory accounting software. There is also the interesting new angle of being able to shift to SQL database. while at the same time being able to lower the development cost as well as increase your competitive advantage? . After all.
And of course. then you will need additional requirements. Here. There are many types of Vb net data grid view to connect to the database. When the information or the data is referred.12 How Programmers Make Use of Vb Net Data Grid View While you are engrossed in creating your databases in accordance with your SQL files. . You can create different forms and graphical accessories which can allow the other users to access as well as view the information. the information which is also stored in such an object like the database and also has a data grid view will also have its own table. This one works in conjunction with Microsoft Visual Studio as well. One way to find yourself in a friendlier environment is to find a way to work with data grid and learn the views. so the programming environment will also appear to be as close to the SQL type of server as well. One of these requirements includes having the ODBC Data Source. you can then create different windows applications. The database table is also what is known as a set. Should you wish to employ other techniques. you can then create as well as manage the different database in the same way you would were you to use a single application. you will realize that there are easier ways to go about this. and the simplest one would be to use the SqkDataAdapter variable since this one will give you better access to the SQL server database. When you work with Visual Studio. the records then are to be called a data set.
If you do not know whether or not to download the new kind. The former has been around for several decades now. then there are some helpful things to consider that will definitely change your mind regarding the matter. and it is time for a change that will surely revolutionize the way developers are going to do their work in the fast-growing dot net business. This is much perfect for conducting tasks in a business related environment and as such proclaims that accounting software must not be written in C++. the new lion of the jungle is the Vb dot net. it is to move from plain visual basic accounting software to Vb dot net. Second. know that visual basic is dead. Here is also another dead end product which does not have the capability to provide you with the resources you need to forge on ahead. First off. . You should avoid following what is said as dead end technology because a lot of advanced tools as well as resources will not be able to support the older time complier.13 Why You Should Consider a Vb Net Download If there is one thing you can do to revive your career in information technology. so there is no reason for you to download it because it is no azalea plant. you should also stay away from Delphi which works in conjunction with Vb net. Of course. When you stay with Vb net you will be quite safe and stable with the leader of the pack. So always move on to better things.
. This is a faster way of arraying data for quick interface display. the For Next statement could be more useful.14 Parts of the VB Net For Each Syntax The Visual Basic syntax For Each is used to make a redundant command for each element in an array. First it should have specific elements. This is any variable statement that can be inserted anywhere between the For Each and Next commands. Second. This is required because this would be event that will be triggered by the For Each statement. These are the programmer’s set of collections. It is a language that will instruct the computer to display an unknown number of data that has been grouped as an iterated set. This is a required entry because the operation of the VB based program depends on the group of elements that have been arrayed for display. Another important part of the For Each syntax is the group which is a variable object and specifically points to the arrayed collection that will be repeated by the For Each loop. the VB Net For Each statement would be the best option. An optional part of the For Each syntax is the statement. if the values of the collection are not known. It will repeat a process unless a Next command is created. However. The Visual Basic For Each syntax is a good way to display a collection using few variable commands. The For Each statement should have 4 key parts. it should have a data type. The data type should be defined if they were not specified in the elements field. If the initial and final values of the data set are known to the programmer.
This type of List code will allow definition of an attribute or several attributes that can be applied on any programming project. Multiple parameters are also separated by commas where the individual parameters will be enclosed in parenthesis. This is very useful for limiting the target objects in a set of different collections. there are three types of List functionality that can be used on the VB Net framework. the program will read the codes and display an interface based on the default object settings. Application of List is not limited by any type of programming element. and many more. it is the code that can specify programming limits. an event.15 VB Net List: Separating Different Program Instances VB Net is a programming language that can allow you to create and display object data list with a single List command. Type parameters are important because it create a place holder for each element in the program. The Type List on the other is a must language that could be used on any generic programming. Specifically. It directs any program to a set of events or procedures that are included in the parameter. First is the Attribute List. If using multiple attributes. types. In simple language. the elements can be separated by commas. procedure. If a parameter List is not defined. interface. Another VB Net List functionality is the Parameter List. The specific attributes of a source program can be found on the Meta data assembly. and . procedures. Attributes List is very helpful when annotating the any programming codes. Based type list. In fact it can be used on all programming elements such as the properties.
16 structure can be applied generically on any programming language or code. .
Sets of code can be applied in order to generate Listview events. size. columns. This is a standard control feature of the framework. Creating a Listview involves only adding this function to a new project. The Listview functionality supports different kinds of attributes. This functionality is an advanced feature of the Listbox interface. objects. date created. The view can be easily sorted whether on ascending or descending list or whatever the user selects. a selection will be provided for the . the Listview will allow these elements to be changed based on the individual preference of the user. and label editing. Users can easily change the list view on the displayed text and objects in explorer. or commands. Multiple data format can be supported by this functionality which includes icons of different sizes. By going to the control features. reordering and hot tracking of selections. Controlling these attributes allow for a more organized display in the interface. and path.17 VB Net Listview: Creating Easy to Control Graphical Interface The VB Net Listview functionality is very important to organize the data that are being displayed on the computer interface. This includes type. By selecting the detailed list. users will be given the complete attributes of a file or folder. The Listview functionality works like the Windows explorer. All Visual Basic editions contain Listview functions. Programming a Listview will generally ease the interface of an application or a set of data that will be displayed before the user. And like the windows explorer graphical interface. It will allow programmers to create multiple options for users on how to view lists.
. an icon will appear on the control form of the project which can now be utilized for creating Listview.18 Listview function. After adding it.
. Set up checks include determining that the static Main class does not have an object that needs to be supported through initialization.19 How to Troubleshoot VB Net Service Application Time Out VB Net Service application can be started or run using a control panel. or it could time out on the users forcing them to restart or reload the application. This can be done by moving the application to a new thread. Some elements of the programming set up must also be checked to ensure that no application time out will occur again. there are instances when the VB Net Service application will reach a run time error. First. All these take time and it will certainly waste a lot of effort and resources especially if the system crashes. This route as is faster and it provides familiar window surroundings. This will usually fix error events and will correct itself the moment a reload will be triggered. It could result to corrupted system.Start command. It is also useful if the inheritor class of the ServiceBase. hang the computer. However. all VB Net timed out error. The good news is. There are many factors that can cause VB Net service application glitches. the computer system should allow the restoration of service through the OnStart function of the service.Start will not load any of its constructor objects. can be easily resolved using the program itself. The programmer must also try to minimize the code before initializing the ServiceBase. Normally. a programmer should ensure that applications levels would be set to defer.
It is also available as a torrent download. Next. . Statements such as Using. For Each. There is a broad range of control that is available with the VB Net framework. The Dispose function will always be called without exceptions. This function helps programmers who are familiar with older versions and just starting out on the new version. the program then will automatically execute the statement. Once the statement obtains a resource. This capability increases the control of programmers to the applications that they are creating. It works by calling the Dispose function once the variable object that was initialized goes out of scope of the statement. The Using statement is specific to VB Net 2005 but it is still supported by the new VB Net framework. End. The original resource then would be disposed. Both automatically dispose an event whenever the parameters for it cease to exist. Dispose.20 What is the VB Net Using Statement The VB Net Using statement is a specific syntax command that can be used to initialize capture or obtaining of a resource or multiple resources. A user can find all the list of command codes and statement the will work on VB Net on the MSDN library. The Using Dispose statement is also similar to the Try – Finally syntax. It is a simple command line much like the other statement syntax being used in VB Net. The codes package is a bagful of commonly used language that has been configured to work as a programming language. and many more are specific command features that will initialize an action.
you can also have an employee who is working a table in a database where there is a particular employee identification for each member.Net Combobox Using a combo box for Vb .21 A Detailed Discussion on Vb .Net 2003 or the 2005 version. you end up needing to store a pair that is called value-text. . Also.net is something which a lot of . While you display the list in an easy manner.net which can help teach this functionality. it is also in this area where they actually experience a bit of a problem. you may try to visualize a scenario where one will need to put on display the complete and detailed list of all employees who are part of a drop down or a combo box. However. it is also a bit tricky to hang on to the twist that is brought about by trying to keep the identification against each corresponding employee name that is found in the drop down. For one thing. there is also no direct method which is readily available in the .net developers work with. Apparently. and you of course will need to have the program Visual Studio . This is because when you work in a combo box or what others call a drop down. This application will also have several requirements in order to run. To illustrate. It is them easy to see how one can be able to access their records by simply referring to the identification of their employees. your computer will need to run on Windows XP Professional SP2 at the very least. whichever you may prefer to use.
But in order to do this seamlessly. which is a way to display the information into several series of both columns and rows.22 Stuck in a Rut? VB Net Datagrid is Your Best Choice If you take a look at things from the point of view of the user. Somehow. as you move some cells from the display controls and move about in the checks or the combo boxes even. To do so. you will also need to learn how to navigate along the cells that are found in this datagrid. These have different intersections which can be called cells. . you will be working with the datasheet display. These categories may be used to figure out the different scenarios you can encounter as you work with the datagrid and monitor the information you work with. There are several categories which allow you to display data which users will manipulate. you can press Tab in a continuous manner in order to be able to move one cell going to another. you can click on the values from one cell and click those in another. This is easily done if one had control of both types of records. the datagrid sheet’s controls will also allow you to do this by pressing the Enter key instead. A datasheet then is a way of displaying all the records as can be possibly displayed in the data grid. you will need a datagrid to piece together the different kinds of scenarios of your data navigation. Additionally. In this light. making each and everyone viewable to most. If you alternate. data navigation is something that involves moving data from one database to another.
there are other properties which one might consider in order to make this truly clear. you also need to learn a few terms in order to beef up your visual basic jargon. should any actually be in existence. Of course. Constraint. This one will determine the returns of collections of the child relations that are found in the data table. are grabbed and maintained in the table – which are figures that you actually manipulate to create change in the dataset. First off. the Columns are the returns of the collections that are part and parcel of this table. you need to know that when it comes to visual basic.23 Terminology You Ought to Know in Vb Net Dataset If you are a newbie programmer. you have a term called Case Sensitive. Here. We are able to create our own table when we use the code by way of a data set as well as the types that are defined in the namespaces. This data table is then what you call an in-memory representation of what is a block of data. So when you create a data set. Of course. This is important because you need to familiarize yourself with the basic information that come with your work – if not. . you need to know if a series of string comparisons that are found in the table are case-sensitive or otherwise. the one thing you need to do straightaway is to learn all about working with datasets and data tables for visual basic net. then you just might find yourself floundering once you are assigned to do more pressing and more confusing responsibilities later on in your job. You also have one called Child Relations. on the other hand. it is one that will allow you to create your very own table and be able to work with them as well. For one.
you will also need to be able to set up a project reference to the type library. it is much easier to control them as well. This is a process which will allow the other applications to be written in languages that are like visual basic and to automatically program the other applications as well. Of course. When this is done. you have an application object as well as a workbook and a worksheet object. As such.net.24 Wise Moves with Visual Net and Excel When you are working with Visual net and Microsoft Excel. this can only be done through the user interface and automation. Good thing about this is that excel is able to expose this programmatic function by way of an object model. Each of these things have a certain amount of control on the functionality of the components that make up Microsoft excel. Automation to excel will also allow you to perform several actions that will enable you to create new workbooks and add data to such workbooks as well. you will probably need to know how to do a couple of commands that are a bit more complicated than usual. . Here. This object model will also be a collection of classes as well as methods that can serve as the different counterparts of the logical components of the program. Once you use excel and other MS office applications. Automation is one such command. almost all of the actions which you can perform in manual mode will be in automatic configuration. you can even use this procedure to create charts. But in order to be able to access this object model that comes from visual basic .
The Split and Len functionality also operate on the same plane. events log. it would be much easier to use the VB Net Format method because of its simpler code values. units or measurements. The Format functionality of the VB Net framework makes it easy for programmers to create user friendly data visualization and interfaces that updates automatically when displayed on the computer. Programmers then will only supply the appropriate object type that will be read by the program and displayed on the computer for ease of reading. and other data type that can be displayed in a stringed array.25 The Importance of the VB Net Format Programmers normally use the VB Net Format method to convert strings of data into recognizable and very specific object type. However. Data can also be easily supplied on the intended field so that arrayed strings can be read and comprehended by the end users easily. It can also be tweaked by using the Format code which is generally supplied in the help pages or in the resource center of VB Net. A string of individual elements like MMMM can be converted into specific month per month display using the VB Net Format method. It can be run using an interface wizard. conversions. This can also be used to display currencies. . There are other ways to display a stringed data array on the computer interface. a string of number can be converted in specific date and time display. The Format method in VB Net should be easy to use. For example.
A programmer can change the default setting for the Listbox view in order to easily navigate through multiple column display.26 How to Make VB Net Listbox Easy to Control The VB Net Listbox is a graphical interface where users can select one or more items from a displayed list. The properties for Listbox sort can be . To display multiple column lists on the box interface. This can help user navigate easily through the Listbox. they can simply select None as the select value instead of the default One. When multiple column lists are displayed in the listbox. The Listbox is written based on ListControl class which can be operated under the main Control class. The VB Net Listbox control interface contains several functionalities. the default setting must be change from False to True. a horizontal scrolling bar can be manipulated to view several columns in the listbox. This can be further tweaked by changing the properties of multiple selections to MultiExtended. This will allow users to simple press the Shft – Ctrl – arrow keys of the keyboard to navigate through the entire Listbox. On the other the MultiSimple should be selected to allow multiple selections of items in the Listbox. The selection of items can also be tweaked through the Listbox properties. To ensure that the Listbox will always display a scrolling bar. the default False setting for scrolling interface must be changed to True. If a user does not want the items in the box to be selected. Individual items can also be sorted according the preference of the user. This will change the attribute of the box and will allow multi column graphical interface.
by categories. . or any other attributes.27 changed to display the list in alphabetical order.
It can be done using the VB net’s own tool box. Although printing functionality with the VB Net framework is indeed difficult to handle. it is advised to utilize third party printing software to handle the function. sizes. If this happens.28 Two Ways to Overcome VB Net Print Function Difficulty One of the most compelling issues confronting the VB Net framework is the difficulty or at worse inability to print the written code or programs. One set back to this method is the inability of some printing programs to wrap the stringed codes and elements of the programming language. A programmer needs to access the components attributes that can be found in the tool box and proceed to capture the target print page. Users are commenting that developers of the programming language is ushering the emergence of a really paperless office precisely because of printing handicap that maybe encountered using VB Net. Another way to manipulate the VB net print functionality is to write a code that will be able to talk to the program. it cannot be said that it is impossible to execute. individual line attributes can be written to determine standard printing codes defining text fonts. There are two ways that programmers are doing to be able to print programs on the VB Net. First. and line attributes. the print display will create a run on set of text the will overflow beyond the paper border. Using a third party program to print VB Net encoded language would be convenient and of course easier than writing a unique code to instruct the framework to create a print preview and print functionality. From this. The third party application should be able to interface and capture the code for printing display. .
29 VB Net SQL: Adding Database to the Programming Language SQL has become a critical component of any class of modern programming application. It involves just a few clicks because the tool box of VB Net is quite similar to other standard computer applications. the SQL icon can be accessed. The downside however is that not every VB Net resources can be prominently displayed on its interface. With so many functionalities and limited screen real estate. SQL provides this basis and this is evident with the wide use and applicability of the database application to program language creation. This will now initialize the integration of a selected database to the main program. This is a refinement from the previous versions thus a VB Net SQL interface can now be utilized. one needs to right click on the SQL icon and select add a database. web. or XML application without the benefit of solid database application. Program developers naturally do not create a client. enterprise. the SQL functionality can easily be overlooked. From the main dialog box of the Server Explorer. Right clicking the added . This will now enable users to create graphical database design in order to integrate it with the main VB Net framework. That’s because some SQL service features have been tucked away in the tool box of VB Net program. one needs to initialize the Server Explorer. To access this SQL database design feature. The good thing about VB Net is its natural ability to integrate SQL functions in its service applications. Specifically.
30 SQL connection will allow users to customize the properties of the connected database. .
It can also be utilized by other programmers either through web interfaces or through a virtual private network. XML programming can also be leveraged to support new versions of the VB Net framework. This increases the capability of the application in recognizing different query languages such as the LINQ or Language Integrated Query framework. That is why the VB Net framework integrates XML schema as one of its major databases utilities. This tight integration could help application developers and programmers to transmit a source code application over a broad range of platforms. the VB Net application will be able to construct a hierarchical data model from linear databases. VB Net specifically supports query languages through its deep integration of XML literals and XML programming properties. This means that it would be very useful for databases and programs that integrate databases in its utilities. It allows multiple users on different platforms to use databases easily. The power of XML schema lies on the fact that it can create marked up files that can be stored easily.31 VB Net XML: Making Databases Easier to Access XML or the Extensible Mark up Language is a very simple and flexible programming language that allows application developers to easily transfer and share text based programming. Using the XML schemas. The program then will initialize results from the query and will display it on a readable format. This capability is very useful also for integration with web applications. The data model then can be used by end users easily by just entering the required attributes for each query field. .
Visual Basic has also written the really hard codes and users will only have to change its attributes and properties for their unique programming projects. The ease of use of VB programming methods will allow for quicker development of object oriented program language. What’s more. That is why generating programming controls and tool boxes would be easier because the basic parameters have been written already. Visual Basic programming certainly eases the methods of creating applications.32 VB Programming: Creating an Easy Environment for New Program Developers. This is radically different from other programming applications and language that will require developers to write voluminous codes just to display a simple interface. It can also be used to display different graphical and object based data. application developers now simultaneously creates written code program while drawing the object on a windows interface. This advantage is greatly enhanced by Visual Basic’s ability to use common windows graphical interface. Through automation of programming. VB programming will involve the creation of applications using some aspects of the windows platform. VB programming or the Visual Basic programming language is not only used to create logical applications through generation of codes. The program developer will only change the values in the language. This is ideal for new developers and programmers. The good thing about Visual Basic however is it provides programmers with all tools that are needed to create exciting applications. New program developers who are very familiar with windows logic will . The Visual Basic framework also qualitatively changed the way programmers approach applications problems.
33 not have a difficult time navigating through Visual Basic’s functions and controls. .
the EXE file of the program can be initialized and the installation will automatically start. It means the programmer cannot use a lower version of VB Runtime for a higher edition of Visual Basic. programmers can run any edition of the Visual Basic framework on their computers. It would be a waste of time and effort because the incomplete Visual Basic . These versions correspond to the different versions of the Visual Basic program. multiple versions of VB Runtime applications can be installed in a workstation. On the other hand. This means the computer must have VB Runtime application installed in its system environment so that it can read the main Visual Basic program.34 VB Runtime: Allowing Visual Basic to Run on Workstations VB Runtime is a distinct application that allows users to use the Visual Basic programming framework. The VB Runtime application must be installed only once on a workstation. the main Visual Basic program that corresponds to the version of the VB Runtime can be uploaded now to the computer. The VB Runtime application can be downloaded for free on most programmers’ websites or in some file sharing and download portals. In this way. It is a small program that will not take up lots of disk space. There are different versions of the VB Runtime applications. Once installed. Once downloaded. This installation process should not be reversed because the Visual Basic program will not work or install properly if no VB Runtime is detected on the computer.
35 application should be completely removed from the system first before any reinstallation can be made. .
The expressionlist line is also a required statement. A comma should separate several expressionlist lines.36 How Does a VB Select Statement Operates? The VB Select statement can run several case statements based on the values provided for recognizing each statement’s expression. The expressionlist statement list the values matching the controls specified on the testexpression line. The other one is the expressionlist that contains the list of clauses or statements defining the values of testexpression. a statement must be entered to terminate the operation. The expressions listed on this part must conform to several accepted data types. At the end of the scripting query. The testexpression code of the VB Select function is a required operator. These are called comparison operators. On the other hand. Words like To and Is can be inserted to trigger different Select values. which are needed in order to complete the Select query procedure. =. There are other control operators that can be used for the testexpression line. The To statement defines the range values required for the testexpression line. The first is the test expression that should be written right after the Select operator. The query cannot be triggered if this operator is not defined. There are only two major parts that must be included in the Select line query. >. the Is operator must be used in conjunction with a value operator such as <. . In this case an End Case statement is needed. The End Case statement will signify that no other operations are needed so it will automatically abort Select run queries. if multiple queries are written.
The source code serves as the specific language that is recognizable by the computer system or the web browser. an application or program will be rendered useless and unreadable by the system. There are also tutorial resources on the some websites that specify step by step approach on how to create a VB source code. Most programmers can develop a generic code for any type of computer operation and they upload it on file sharing networks. For the scripting code to be useful. it must use standard coding language that can be understood by the computer. That’s because the coding instructions include special actionable statements that are commonly used to create codes that can be comprehended by the computer.37 Where to Find Free VB Source Code Almost all computer operations. directories. these source codes are distributed for free. . and XML operations. applications initialization. and forms control also use VB source codes. Files. Games. and networking protocols all use source code scripting. In many programming websites. web interfaces and event handling use a type of VB source code. Without a source code. HTML. It can serve as tools and guidance on how to create and write source codes that can be utilized for common or complex operations. Of course one needs basic knowledge in Visual Basic programming in order to understand the instructions provided on coding tutorials. multimedia. VB source codes are generally available on the Internet. VB source codes are utilized on ASP. New programmers can take advantage of these source codes to further boost their understanding of VB source coding. It will be just a set of incomprehensible text.
In this way. However this kind of system reconfiguration may not be suitable for all real time applications. The solution for this issue is to create a DoEEvents and QueryPerformanceCounter loop system. its resolution would fall below 50ms output. the timer will not be affected by any VB IDE meltdown and will continue to function on the ActiveX path. . Normally. That’s because for complicated programs such as audio systems. the usual VB timer may not be suitable. Another approach that can be taken is write a new set of VB timer code intended for higher resolution output.38 How to Ensure Stable VB Timer Coding System Standard VB timer is a useful application for simple programs. for high impact multimedia programs that need timer utility. The first step in this process is to code the timer independent of the main VB IDE framework. which would be ideal to run audio systems and other multimedia applications. the coding system must be done using the ActiveX DLL platform. The code must be able to produce at least 1ms to 10 ms resolution capability. the VB timer must be able to muster a 1ms resolution capability so that it may produce an accurate and crisp output. standard coded timers could not produce this kind of resolution thus sacrificing the quality of audio output. However. Coding VB timer on higher versions of windows may speed up its capacity but when it is run on an older version of OS. To do this. This kind of resolution is so slow it would not be very useful for most multimedia applications.
39 Where to Find Free Visual Basic 6 Download Anyone who wants to learn programming using the Visual Basic 6 applications can easily download it from file sharing sites on the Internet. The new version also incorporates several program fixes. The VB Runtime application is a required program so that the Visual Basic 6 could run on the local computer. Learning and mastering the Visual Basic 6 programming language hold several advantages. a VB Runtime application must first be installed. A VB6 Runtime application is a free program and can be downloaded from almost any programming portal. Although not many people are using Visual Basic 6 program. the quality of some of these programs could be questionable. It will only involve registering or signing up with the Microsoft network and a complementary enterprise class Visual Basic application can be made available. There is a 2008 version of the Visual Basic application that could offer more tools and utilities. The programming skills learned through the program could help enhance the technical capabilities of any IT professional thus opening new employment opportunities and career advancement. However. It is advisable to get the latest service pack of the Runtime application in order to get the latest fixes and patches to program. Other websites that are run by programmers also offer torrent downloads of Visual Basic 6 applications. It can also be downloaded from the Microsoft Visual Basic page. Before installing the Visual Basic 6 on any computer. . it could be very useful as a study platform to learn the ins and outs of VB programming.
It involves writing the source code of the database so that it can synchronize with the data in Access. Programmers of Visual Basic and . ActiveX Data Object is the ideal bridge application that allows seamless integration of Visual Basic to Access. The developer should open a database in Access in order to initialize automated integration. tables. This is a more practical approach especially if the programmer will create lots of objects based data such as forms. both application should be running on the workstation. Any programming language needs a database support in order for its operations to work fully especially if the intended application will be used to query data and produce results that are driven by several data queries.40 Visual Basic Access Automation: Overview of VB Automation with Access Program The database Access office application can be synchronized and integrated with the programming platform of the Visual Basic program. it will establish connections with the Access utilities to pave the way for more enhanced programming capabilities. queries and graphs.Net application can use ActiveX Data Objects or the ADO.NET in order to integrate Access database. There are also ways on automating the integration of Visual Basic with the Access database program. In this way. To automate the integration of Access with VB programming. the created codes will . Then use the Visual Basic interface to generate the codes that can be grabbed from the Access program. The OpenAccessProject command must be utilized to create the environment needed by Visual Basic. Automation will ensure that whenever a VB application is launched.
.41 implement the object display including the data in Access program.
copying. This then can be integrated into the main Visual Basic programming set up. any programming applications can also use the ActiveX data object. Specifically. The best utility of the ADO or ActiveX control is its programming language neutrality. First. Second. when a programmer starts a Visual Basic with advanced databases project. The data access object can provide a clear interface with any database program. From the VB program.42 Visual Basic Database: Using Third Party Applications for Effective Interface Visual Basic database projects will use three distinct programs or scripting applications. Any Windows application especially Access and Excel are capable of exporting and linking their data through the OLE DB provider. programming a project with database will need an application called data access object or DAO. the ActiveX Data Object or the ADO must also be used for databases projects in Visual Basic. graphs and images from a database . This utility then can be picked up by the ActiveX data object controllers and can be integrated to the main Visual Basic programming interface. ActiveX operation works by displaying database elements through OLE DB provider. appropriate value conditions can be written in order to properly display the interface provided by DAO applications. This means that aside from Visual Basic. resizing and pasting objects. These third party applications can be fully integrated especially in Visual Basic versions 5 and 6. the following applications will be required. Finally simple data bound controls for editing.
This will allow the Visual Basic program to easily code source objects from any applications with databases. .43 application to Visual Basic can also be used.
Furthermore. one can say that the Microsoft Visual Basic for Applications or the VBA is one type of embeddable programming environment which is designed to help developers build different types of custom solutions that allows them to make full use of Microsoft’s Visual Basic application. and would thus not need any additional enhancements. This one also comes with a visual basic for applications software development kit. Take caution though. These developers are the ones who use the applications which also host the visual basic for applications.44 Getting to Know Visual Basic for Applications A lot of people wonder what makes the VBA or Visual Basic for Applications a truly useful part when it comes to information technology. because the software development kit is also not a necessary tool which can help develop different solutions which are already using visual basic for applications and are hosted for evaluation purposes – like Microsoft Office. upon purchase. It actually contains the different documentation and the tools which can be used for hosting visual basic for applications – meaning. such can be automated and extended with regard to application functionality. To answer such a query. When you use the software development kit. everything you could possibly need in order to evaluate the visual basic for applications in your work. The reason for this is because Microsoft Office already includes in its roster the visual basic for applications. . you can then be able to have a way to easily integrate the visual basic for applications for evaluation purposes. thus shortening the cycle of development of these custom business solutions.
This is because this visual basic program also helps you by allowing you full use of the different sets of tools which you can use in order to create even better and more useful applications.45 The Great Facets of Visual Basic Program When it comes to programming. However. Visual Basic stands out from the rest. One example could be that the controls which you use could be in the form of a button. . you are making the conscious decision to make your like a lot more easier because you have such tools. you can come up with applications that also make use of the different parts of windows. Some of these other programming languages are Pascal or C. and then you have to write the code itself which would then be instantly executed as soon as the control button can be pressed. you can create the control which can also be found on the screen. Since you use really great controls. To start off. many programmers and software developers can probably say that they have witnessed undergoing a definite major change throughout the years of programming different types of machines. One example could be that what used to be constructed in just mere minutes via the help of Visual Basic could also find its equal in several days when you decide to use a different programming language. and thus have the real hard code already written for you (instead of slaving away trying to come up with it yourself). When you choose to go with visual basic.
of course. then you need to install the runtime component that is also version six. you might try downloading and installing all four of them . When you do. If you do not know which runtime version to use. While the programming language is easy to learn. The version which you will user for your runtime is one that is depended on the version of the actual visual basic language you have and used in order to create the program itself. you need to install the visual basic runtime before you get to run the actual program that is written in visual basic itself.46 Visual Basic Runtime: First Things First If you work with Microsoft Visual Basic. its files are then automatically shared by every type of visual basic program which you will install subsequently. because if you do not have the program that created the application then the computer will more likely be unable to recognize it and thus fail to have it run at all. One example would be that if you run a program that was written in visual basic 6. and each one came up for all the different release dates of the visual basic programming language itself. Right now. you might have encountered several things with the run time. Quite logical. However. To start off. there are still some things about it which you might need to have a little expounding on in order to make things crystal clear. the great thing about this is that you will only need to install the runtime only once. there are four different types of visual basic runtime.0.
The advantages of using third party applications for VB print functions include allowing pro- . VB print preview is important to view created forms. forms. and diagrams. and dialog boxes. It will also be able to provide object view support which was originally embedded on the Visual Basic printer preview function. Most VB print programs will be able to display different modes of resolution and printer settings. Some VB print applications can also import or export text files and documents and convert them to windows metafile. Users may encounter some difficulties with the Visual Basic framework print capabilities. The ability of the print applications to recognize several programming languages also make them extremely useful in displaying bitmaps and other images created in other format. charts. with the use of third party programs for print preview and printing functions. It will also support different graphical display such as graphs. panning. windows.47 The Advantages of Using VB Print Applications There are many third party applications and programs that can provide print preview capability for Visual Basic. However. Several useful functions can also be utilized through the VB print preview applications such as zooming. Visual Basic print preview programs will also support other graphical display of different applications like CAD software. The print and print preview application of Visual Basic can also serve as a flexible and compact report generator which was supported in the past by bulky and unwieldy programs. the difficulty could be resolved easily. and resizing of graphical display.
48 grammers to display their program’s graphics on an easy to read format. .
First. and compare parameters. The find command will search for the old values or old texts within the string that need to be replaced. the string parameter must be specified. specific line parameters must be written. the new values or texts must be preceded by the command line replacewith. This is a required line and should be the first in the array. There are other optional values such as the start.49 How to Initialize the VB Replace Function The VB Replace function can be used to find and replace an old written string with a new one. This is a required parameter and should always be part of the syntax string. These optional values could be included in . For initializing the VB Replace operation. count. the find parameter should also be specified. These three parameters of the VB Replace function are the essential elements that must be written by the programmer. Third. That’s because the Replace operation will work only based on the specified string entered by the programmer. This is a convenient way of modifying scripts and codes for an arrayed collection of elements. The replacewith parameter forms as the sub-string of the entire syntax. the programmer should now specify the new texts or values that will be entered in the program. Second. Writing the find command should be specific and should conform exactly to the written format of the target values or texts. The Replace function of the Visual Basic programming framework essentially automates the editing and modification procedures for program scripting. An application developer can easily use several command syntax of the VB framework to execute the replace operation. Specifically.
If they are not included.50 the syntax. the program will treat these optional values as set to default. .
Event handling must be written manually within the script itself. VB Scripts however cannot be debugged compared to full Visual Basic programming. all Windows operating system and the Internet Explorer program has an embedded VBScripts in its programming. it must be edited on a text editor. and a web browser. VB Scripts allow users to create dynamic images. and other tools and functionalities. Specific handles must be included in the language so that it can find an appropriate handler when a procedure kicks in. Any windows based computer can be used to create VB Script using only a standard text editor. web browser. To change the properties and controls of the VB Script. and HTML pages. In fact. The VB Scripts technology is smaller and more compact programming tool than the Visual Basic application. There are no special installations required especially if the computer system has the updated and latest versions of ActiveX controllers and windows operating systems. . web pages. It should only be embedded in the HTML pages. objects. VB Scripts do not have to be packaged into an EXE file to be deployed. The VB Script language has no event handler compared to Visual Basic. form controls. and ActiveX controller. The VB Scripts can be inserted on the HTML pages and it will be instantly displayed as a complete object or image on a web browser. Browsers will be able to read the language and display whatever object is written on the VB Script.51 An Overview of the Functionalities of VB Scripts VB Scripts or the Visual Basic Scripting Edition is a language that can be deployed on any computer system.
and any others have their own VB source. Such mundane tasks like dragging and dropping functionality in a desktop computer involves scripting source code for it. most source codes can only become operational on specific Visual Basic version. Other more commonly used computer tasks such as form page centering. almost all computer operations use codes to generate the procedures needed to execute an event. The VB source serves as the language-scripting operator. There are many VB source samples that can be downloaded from the Internet. and server side operations. There are VB source for client side operators. New programmers can use these sample source codes as their template to understand the basic structure of VB coding. objects. Other common computer operation procedures also have different VB source codes. The codes for each would be different because each VB source has different events procedures. That is why VB source is very important and learning to write or reengineer codes should be a basic skill of any programmer. display path for printing. VB source can be differentiated based on the configuration of script and the targeted users of the code. It can be rewritten or reengineered according to the individual coding requirement of the programmer.52 What are the Uses of VB Source Codes? VB source or more commonly known as the source codes are prewritten scripts that can be used on Visual Basic program framework. cut and paste operations. In fact. On the other hand. . Some VB Source is version agnostic. This means that the codes and written scripts can run on any version of the Visual Basic program.
The Split function is useful for creating text or data that should be arrayed vertically. If no delimiter is specified. That’s because the default compare values will be used instead if this part of the string is left open. It is a required expression string that includes range delimiters and sub string codes. The values 0 and 1 will be utilized to determine binary compare or VB text compare. the default value will be triggered. The delimiter line statement can be specified or not so this code is basically optional. This means that –1 would be the default count of the string which will return all sub strings.53 Parts of the VB Split Operations The VB Split function can be utilized to create a onedimensional iterated array based on zero values. If no count value is entered the default value will be used. A count value should also be specified if the programmer would know the exact number of values that needs to be returned. The first parameter that should be used on the Split operation is the expression syntax. objects. However this is an optional operation. In this case the space character is the default range value. This function uses the syntax Split to specify different parameters. . It is commonly used on specific sub-strings of a set collection. and numbered values will be displayed as a list. The compare syntax of the Split statement is also an optional entry. Each individual line is separated by a hard return thus the texts. These parameters are also called parts of the entire Split syntax.
the voluminous resources that that are associated with it will certainly require lots of code rules reading. The video files can also be downloaded from the Internet. These resources are all downloadable materials. most VB tutorials come with sample or practice codes for most standard applications and VB functionalities. Fortunately. Some tutorial sites only ask for a paltry donation for their services. there are VB video instructions and step by step guides. . For beginners who are more at ease learning through multimedia tutorials. Compared to just reading lots of text string. Some tutorials are provided free on the Internet.54 How VB Tutorials Help New Programmers? VB tutorials could certainly help anyone who wants to learn the basics of the Visual Basic operations and functions. These VB tutorials websites provide text notes and instructions on how to use the standard coding systems of Visual Basic. Lots of reading maybe required just mastering any introductory approach to Visual Basic coding system. Although the VB6 version of the program has been touted as the easiest programming application to date. the video VB tutorials would be more advantageous for new Visual Basic programmers. so it can be studied at the leisure of those wishing to learn the Visual Basic programming technologies. These video tutorials are very useful because the actual coding operations can be viewed and explained by a competent programmer. At the cost of $1 per download. These code samples are prewritten generic language that can be used as a guide in creating more complex VB language.
.55 this could be an inexpensive way to learn Visual Basic from home.
This platform is a good utility to learn the fundamental steps in programming using the Visual Basic framework. the Visual Basic 2005 Express must be downloaded and installed on local computer. There are also other resources that can be grabbed from the Internet. The . While tweaking the application. these manuals should be at hand to determine the processes involved in Visual Basic programming.56 Visual Basic 2005 Express: A Good Platform to Learn Basic Programming The Visual Basic 2005 Express can now be downloaded as a free application. The document specifies the step by step process of how to begin programming using the VB 2005 Express. one should download a zipped package of VB source codes. For new programmers and for those who want to start learning the Visual Basic application. Within the Visual Basic 2005 Express. In this way. the VB 2005 Express could become their learning vehicle. To know coding structure and systems. the application will work fully and glitches could be avoided. Manuals and electronic handbooks such as programming guides can be acquired also from the Internet and some VB programming portals. Be very sure however to install a Runtime application before trying to upload the VB 2005 to a local workstation. To start the learning process. These sample codes will work if deployed on the Visual Basic 2005 Express. It would be advisable to thoroughly read this document before attempting a trial and error programming using the 2005 Express. there is a built-in help tutorial page.
.57 The codes then can be learned easily because all required operations needed to build such codes will also provided through a text document.
The use of Visual Basic array has many disadvantages. But if no applicable elements are available. Individual states will be its unique elements. It will allow programmers to systematically display different set of elements with simple values assigned to them. To make a script or write a programming language using Visual Basic array. As long as there are applicable elements that can be looked up. other syntax operators may be used to qualify the look up operation of the program. the operation will continue. In this way. So. for every state. As an example. The programmer can assign unlimited index numbers especially if many elements are present on an array. programmers need to know the exact number of elements available for each set of array. then a Dispose or Terminate syntax can be written to close down the scripting language. These elements can be assigned unique subscript using index figures with the value 0 as a starting element. Indexing can go on as long as there are elements in the array. a country may form as a distinct array. assigning values would be easier. . If the exact number of elements cannot be determined. This makes it possible to assign a single value or name for a whole set of array. The array can be divided or differentiated by assigning a subscript or unique number for each element in the array.58 The Importance of Creating Visual Basic Array Visual Basic array is composed of different entities but share the same logical values. an index number will be assigned.
.59 Arrays are also useful for database purposes. In fact. most Visual Basic array program set up is utilized for large data integration and to answer queries that will require numerous results.
running with the lightweight SQL Server compact edition and you can also use the 2005 express edition of SQL Server. You are also able to integrate two dimensional and three dimensional graphics here. you can be sure that you will get the latest enhancements for your Visual Basic express edition. This is a simpler tool to allow you to increase work productivity and come out with better outputs. which is also quite the powerful client and server workhorse. Visual Basic express edition also allows you to create applications that are data-enabled. From here. And with the help of Intellisense support. While it does not stop there. You can design different types of Windows presentation foundations type of applications that have built in designer support as well. as well as add different objects to Visual Basic. it is quite simple to use this Visual Basic express edition. To begin. These are some really great features of Visual Basic express edition indeed! . Aside from this.60 The Cool Features of Visual Basic Express Edition Many users of Microsoft’s Visual Basic program are going to rejoice over the fact that their must-use application now comes in an express edition. it is also good to know that you are going to have one cool application which allows you to add some pretty neat effects as well. you can choose to build different applications when you use the language integrated query or the LINQ – a strong point which can add data querying capabilities for both SQL Server and XML. as well as the integration of both audio and video controls.
Some of it may come in CD format while others are published in printed editions. the first resource could be the embedded how-to help pages of the program. the topic will be displayed in alphabetical order. Some of these manuals are available in PDF files and can be easily downloaded. A developer needs to download several advanced manuals that can help specifically in coding and troubleshooting Visual Basic.61 Where to Get Visual Basic Help to Solve Program Issues? For Visual Basic help. All possible answers to a query can be provided with a general answer using the Visual Basic Help section. . The Visual Basic advanced functions and advanced code debugging and troubleshooting techniques could be acquired from these resources. Just clicking the help button in the toolbox can access it. On the other hand. purchasing or subscribing to a service will enable programmers to access some of the best tutorials and help resources. The good news is it can be utilized using an indexed query approach. Aside from these materials. the help index of the Visual Basic program could be insufficient. there are online programmers forum that provide support for new VB programmers. Visual Basic help resources are widely available whether on the Internet or in published materials. For solving more complex problems. These are good reference materials that can be used a practical guide for any problem encountered in Visual Basic programming. New programmers will not experience great difficulty solving the issues encountered during VB programming. So. These forums can also be a good source of Visual Basic help and tutorials.
you can also then utilize the user interface. It is also a type of graphical development environment which one can only describe as complete with all the bells and whistles attached to it. This is definitely better compared to the other programming languages which have more complicated commands. you might be familiar with Visual basic.62 Why it is Better to Get into Visual Basic Programming If you are a software developer. this Microsoft Visual Basic is not just your regular old programming language. a part which can then collect the different user inputs and also be able to display the various formatted output in a way that is more appealing and useful than useful – especially when compared to the different versions of SQL that are also capable of achieving this. But if you must know. When such happens. You might have worked with it at one time or another as well. sort of like the ones you can find on an Excel spreadsheet. Perhaps the best thing one can say about Visual Basic is that it is easy to use and will also allow many a user to come up with really impressive-looking kinds of graphical programs – by using little coding by the actual programmer. Such an environment will also allow the users who have very little programming experience to be able to easily develop many useful applications which can run on Microsoft Windows. . The Visual Basic also has its own ability to develop such programs which can then be used as a type of front end application connected to the database system. These applications they can make can also then have the ability to make use of object linking and embedding.
An array that holds other arrays as elements is known as jagged array or array of arrays. called an index or subscript. An example of an array is the number of students in each grade in a Catholic school. An array where one index or number is made reference is considered one-dimensional. The individual values are referred to as the elements of the array. There are three Visual Basic keywords used in array declaration: 1. Public is a statement used when programmer makes the array visible anywhere in the program. However. Arrays in Visual Basic allow programmers to change size but not the type of arrays at run-time using the ReDim State- . 2. An array allows you to refer to these values using the same name and to use a number. The number index starts with 0 through the highest index value. and 3. Dim is a statement used when programmer wants the array in private to the procedure in which it is declared.63 What are Arrays in Visual Basic? An array is the most common form of data structure used in the collection of similar items of the same data type. Jagged arrays can be either one-dimensional or multidimensional. uses a number called as index or subscript this is in order to differentiate one from the other. you must declare the array and its scope. It refers to multiple values by the same name. to tell them apart. the use of more than one index or subscript is called multidimensional. Before an array can be used. Private is a statement used when programmer makes the array visible only to the form or module in which it is declared.
64 ment. They tend to shorten or simplify your code. . which allows you to make loops that deal efficiently with any number of elements.
the Microsoft Office family developed a programming language where the application of Access.65 Excel Application within the Visual Basic Program Microsoft Excel is an office application used frequently in the Visual Basic Application (VBA). Microsoft Excel is a spreadsheet application. It was called MACRO commands in earlier days. Transfer data in an array to a range of cells 3. The VBA Excel allows users to write code. The most common approach to transfer data to an Excel workbook is by Automation. and messages. dialog boxes. which provides users with simple to advanced ways of creating and managing any type of list. Transfer data in a cell by cell 2. menus. To make it more powerful. The following are approaches to transfer data through automation: 1. It automates repetitive tasks and enables user to perform custom command buttons. Make a Query Table on an Excel worksheet which consists of the result of a query on an ODBC or OLEDB data source . Excel and Word can be used in VB. and/or their cells. which can automatically perform commands on a workbook. With automation. columns. Transfer data in an ADO recordset to a range of cells by applying the CopyFromRecordset method 4. there is flexibility in specifying the location of data in the workbook. worksheets. The Excel VBA allows user to add custom features based on user requirements. Outlook. VBA is a computer language that was based on Microsoft Visual Basic. where you try to assemble a series of keystrokes and Excel will learn and do it for you. rows.
. thus saves time and money as well. Transfer data to the clipboard and paste the clipboard contents to an Excel worksheet Excel Visual Basic makes computing easy.66 5.
RDO. and Timer Controls etc. . or ADO. The last version of VB was released in 1998. A VB programmer is able to add substantial amount of code using the dragging and dropping controls like buttons and dialog boxes and define the appearance and behavior. It is known as the event-driven language. Pascal. It enables programmers to build prototype applications quickly. It was in February 2008. C++. and Java. Text Boxes.NET became the designated successor. defining its attributes and actions. making the programming language a dynamic application. that Microsoft extended support ended and Visual Basic. and creation of ActiveX controls and objects. VB allows user to modify and customize based on requirements even during run time. Programming languages where VB was applied includes C.67 Things You Should Know about Visual Basic The term VB stands for Visual Basic. It is a combination of visually arranging components or controls on a form. It is language used by software merchants. and writing additional lines of code to provide more functionality. inasmuch as each object reacts to different events once the mouse is clicked. programmers and developers in producing graphical client request interface. the access to databases using DAO. VB was designed in such a way that it is easy to learn and use. VB has been the norm for programming languages since 1991. VB uses several tools for placing controls on its List Boxes. VB was derived from the BASIC language. VB is a programming language developed by Microsoft. other than its default values. Radio Buttons. that provides the ability for programmers to perform the rapid application development (RAD) using graphical user interface (GUI) applications.
Included most often in the listbox are common answers that you are likely to get. It is used as a link to read and write data in the database field. Users are not provided with typing alternative. A listbox is a window that has multiple strings in it. Listboxes can be either preset in code or built "on the fly. There is a tendency that code cannot be read if they are cluttered with many unnamed or numbered objects. the code determines which entry the user has chosen and its numerical position on the list. which can either be check or unchecked. You need to name the listboxes as soon as you have created a listbox. Listbox in Visual Basic is useful if you want to gather information from a person without the need to input them. based on the type of questions asked.68 What Visual Basic Listbox Can Do? The Listbox is one of the intrinsic controls in Visual Basic programming language. It is important that you create a logical label that reflects the value of your listbox. The values are based on predefined lists and are read only values. Its graphics display is patterned with an ImageList control. After the listbox has been created and filled out. It allows users to see and select multiple values at one time. ." showing the choices in a box of any size and is scrollable. You should plan for the appropriate size or width to use. Listbox normally has a clickable checkbox interface.
4.69 How VB6 Arrays Differ from VB. the lowest bound array index that can be used. if 4 elements were declared as an array. The GetUpperBound method in VB.NET creators had to “homogenize” the arrays prior to becoming a part of the . 3.NET arrays starts from the element 0.NET Arrays When the VB. VB.NET is equivalent to the UBound statement in VB6. 2.NET Arrays were derived from the Array class in the System namespace. VB6 uses the old-fashioned functions like UBound(). By using initializer syntax described as brackets. the former being accessible by all . VB6 has the option of setting array index. it will have only 4 elements ranging from 0 to 3 unlike in VB6 there will be 5 elements declared as the range will be from 0 to 4 in the array. VB.GetUpperBound(0). it has become a controversial topic for many developers because the .NET was first introduced. The following are few differences between VB6 and VB. Visual Basic . In VB. An added feature in the VB. VB. The dimensionality of an array pertains to the .NET uses code like MyArray.NET arrays. Developers have made comparison on the performance of VB6 and VB.NET has no concept of fixed length arrays unlike VB6 where fixed length array can be declared.NET-enabled languages.NET arrays: 1. programmers can define a variable at the same time during array declaration.NET array is called the initializers.NET.NET framework.
Arrays make coding shorter and simpler. . you can specify up to 32 dimensions. which tend to reduce the use of repetitive code.70 number of index number used to identify each element. NET. The VB. In VB.NET array allows you to use built-in methods for sorting and searching.
the service pack version. Users are able to create programs just by learning few of its features. Of all the programming language. DSL or Cable. . There are other related download programs that maybe downloaded which provide updates to the VB version currently used. The User is given two options as to whether installation be done immediately or copy the download to the computer for later installation. date of publication. Instructions are provided on how to start the download. Windows ME.71 How to Get Visual Basic Download and Updates Visual Basic is a programming language considered as the fast and easy way to create programs for Microsoft Windows. It provides a brief description of the executable file to be downloaded and to include the file name. Windows 98. in order to start the downloading. which can be Windows 2000. download size and estimated download time if running on dial-up. Should user. decide to install immediately. or Windows NT. The Save or Save This Program should be selected if installation will be done later. VB has complete set of tools that help new Windows programmer simplify the software development. The programming language as developed by Microsoft’s has provided download executable files to almost all versions of VB. the Open or Run This Program button should be selected. VB is the most used language for it is user friendly. Windows 95. To download the Visual Basic program is to have a PC that runs Microsoft’s Operating Systems. language used. A download button is available on the Microsoft website for the user to click.
The system requirements to install the Express Edition would require the computer to be running under Microsoft Operating Systems either on Windows 2000. x64 or Vista. and free VB codes shared by VB users. there are free VB tutorials available which discuss the step by step in learning the VB language version. The Express Edition allows users to create programs within the . The VB program is a commercial product. that you can imagine the programming task it can accomplished. however. The Microsoft Developer Network provides a Guide Tour of learning and understanding the VB language. how to work with databases. XP. 2003. The Microsoft Visual Basic 2008 Express Edition is available for users to download for free. free VB trial software which gives the user the feeling of how user friendly the program.72 Learning Visual Basics For Free The Visual Basic is the norm programming language since 1991. Other than Microsoft’s Guide Tour on VB 2008. a subset edition is available free while the full development environment must be bought. use forms and controls in order to create a user interface. and produce a user interface for a Windows Presentation Foundation application. Users are given free VB tips on finding and fixing errors by use of debugging tools. The Visual Basic language is so powerful. Because VB is the most common programming language used. and write and read text files using the File System etc.NET framework. . The program VB 2008 has the MSDN Express Library and the Microsoft SQL Server 2005 Express Edition. there are various free VB features that are made to users as well.
2. A specific element in an array would have an index number as reference. Index number by default starts from zero. A unique index number identified for each element of an array. The “Erase” statement allows a quick way in removing values from an array. . The number of elements in an array can be a fixed number or be re-adjusted dynamically. Visual Basic (VB) supports the array concept. 2. A change made on one element of an array will not affect the other elements. Arrays have different kinds and these are: 1. as a built-in data structure having the following features: 1. is a collection of cups. An array should be associated with a variable for referencing. 3. wherein each cup in the collection is able to hold same type of data and where every cup in the collection has the same name. 6. Control arrays refer to a collection of controls having the same name with an index as reference. The collection of data elements of the same data type can be stored in an array. 4. 5. To illustrate an array. Each cup has an element and a number assigned to it that shows its position within the collection.73 What Is a VB Array? An array is a collection of similar variables that contains finite number of elements and of which each has a common name and data type. Each element in an array has a unique index number. Variable arrays refer to a collection of variables having the same name with an index as reference.
. User Defined Arrays refer to a collection of variables having the same name with an index as reference and have multiple pieces of data for each element of the array.74 3.
2. It is the evolution of Microsoft's Visual Basic (VB) implemented on the Microsoft . While VB 6 includes limited support for object oriented design. It is Object-Oriented.NET is not backward compatible with VB 6. .NET) is a computer programming language that is object oriented. Some believed that Visual Basic. VB. It uses “objects” and these objects interact to design applications and computer programs. It has enhanced Event Driven.NET (VB.NET (VB. The code written in VB 6 will not compile using VB. VB. The following are some of characteristic traits of the Visual Basic. however it is not true. It is also referred as a multi-purpose programming language suitable for most development needs.NET framework.EventName clause. It has .NET Framework.NET becomes the successor.75 The VB.NET and its Characteristics The Visual Basic.NET.NET is the new incarnation of VB 7.NET) is a computer program language designed to be object oriented.NET: 1. VB. VB. Events are not recognized as a result of certain naming convention but are declared with a Handles ObjectName. The version 6 of Visual Basic is the last version and Visual Basic.NET includes a full blown support for object oriented concepts. NET is designed with Rapid Application Development which provides several tools that shortens development time. The event handlers has the capability of declaring runtime use of the AddHandler command.NET runs on Microsoft’s.NET framework. that allows full access within the framework of Microsoft’s supporting classes.Visual Basic . 3.
and enable access to the Internet. registry. and more. event log. . file system.NET class libraries.NET applications to communicate with databases.NET applications have access functionality in the . The Microsoft .76 VB .NET Framework consists of thousands of class libraries that allow Visual Basic . system information.
buttons. On the form window is a tool that is used to place controls such as text boxes. and DLL files primarily used in developing Windows applications and interfacing with web database systems. VB allows programmers to create simple Graphical User Interface (GUI) applications as well as develop complex applications. which makes easier for user to modify or customize the program without the need for writing many lines of codes. VB is a garbage collector that uses reference counting. It has default attributes. 5. VB was based from BASIC (Beginner's All-purpose Symbolic Instruction Code) which provided nonscience students access to computers. It uses a style of computer programming wherein the flow of the program is determined through sensor outputs or through user actions such as mouse clicks. 3. VB is capable of creating executable (EXE files).77 Visual Basic and its Features Visual Basic (VB) is a third generation programming language developed by Microsoft in 1991. 2. etc. 6. It has a large library of utility and basic object oriented support . It is associated with Microsoft’s integrated development environment (IDE) used for its COM (Component Object Model) programming. The following are some features of VB: 1. and defined control actions. VB allows programmers to insert additional line codes for more functionality within the event handlers.ActiveX controls. 4. VB is considered as an event-driven program. key presses or message passing from other programs. VB has Dialog boxes that can be used to provide pop-up capabilities. VB forms are created using the drag and drop techniques.
Specifying the attributes to the supposed actions of those components for functionality. Of course these programs are not rudimentary. can be designed and created by the programmer without him having to compose long lines of program code. default attributes are already defined for the components. In this. the applications are not sacrificed at the altar of making it user-friendly. which is really something to be happy about as creating a program is now an average easier than before. more and more developers have started to include and develop other programs that can be utilized by inexperienced programmers. but what makes it different is its default attributes. and reliability in making applications. but helps and aids them in developing more complex applications as well.78 Microsoft Visual Basic: Programming is Easier Programming is known to be an area that requires special expertise. In these programs. . doing programming work in Visual Basic is done through a combination of visually arranging the components to a form. for as long as it’s simple. which is really like the other programs. And one of these programs is Visual Basic. Now a program. which has been designed to strike the proper balance between easy to learn and use. The Visual Basic’s language not only allows programmers to create simple Graphical User Interface (GUI) applications. and through time. which in effect brings down the timecost in the creation of programs.
79 Also. programming can now be easily taught to non-programmers in an easier manner and environment. as in the case of schools for example. with Visual Basic. .
And in using this. where all sorts of Information about Visual Basic can be asked and known. knowledge about other programs are also widened in such a way that programmers can generally discuss these in their own groups. place. the programmers even get to know more programmers and with this affiliation with others. In VB Access. and answered as fast as possible.80 VB Access: For the Queries to the Questions Visual Basic’s greatest achievement so far it that programs can be created easily with its use. answers are delivered at a much faster pace than a book does. In terms of usage. Just imagine the hassle of trying to find the correct solution in a book when the answer could be asked in the Internet. who have many questions about Visual Basic. the need for Information increases. And it is still evolving even more. it is also one of the most-used programs today. all programmers with queries and answers to these queries about Visual Basic can post them in this Website. and in that it has been very successful. This is an excellent Website to visit for people. which leaves something good for the tastes of its creators at Microsoft. It is like a worldwide friendship site. and it is even easier. and as more and more programmers start using Visual Basic to perform their programming needs in relative ease and convenience on their part. . This is why Visual Basic Access was created in the first In this Website.
and in this way. their topics are neatly posted in front.81 These groups. are like conference calls on the chat rooms. so using the VB Access is made even more convenient to use. .
which is a plus considering that programming skills are what programmers need to develop as quickly as possible in this fast changing world. records and graphics. To make it even more convenient. In terms of use. there are still others that come at a fee. from the mere adding and to the deletion of printing. These database projects also contain three separate and different programs meant solely for the use of the programmer.82 VB Database: Training through Database Projects There are of course many Visual Basic database projects that’ll sure to help any programmer in increasing his effective use of the program. as it has been designed as such. these programs show and explain the more advanced uses of Visual Basic with its databases. there are even programs that seek to help the inexperienced programmers in their quest to master the program. the difference will be seen. and this is what they need to excel in this program. . these products are considered free. mastering it is still hard for some. There are even many programs to choose from in this database projects. which may seem as unsophisticated and too simple to even improve one’s talents in programming. These projects also include the explanations about the data bound controls. On another note. all include the use of the Data Access Object (DAO). in which topics to be covered. as well as the well-known ActiveX Data Object (ADO). And though Visual Basic may be an easy program to use. and while some may be free. but with increase usage of these projects.
83 In this. choosing the best possible program will help in the decision-making process of which program to try out. .
there is no doubt that it is something that will be present in the future of computers even more. but clearly automation is better than manual functions. it would allow the user to start actions automatically without going through the user interface. In this. In this automation process in Excel. Excel was made famous because of its automation process. virtually every action to be done would be encoded into Visual Basic and from that point on. nearly everyone says. In this time. the program would be the one to run the necessary Excel application. In saying this. of course except human error. In this case Visual Basic would start to programmatically move and control Excel as well as other applications if the right codes are encoded. is that it is a company that continues to provide support and upgrades to its programs. In this way. which can still be improved with the use of Visual Basic. it would be really correct. which is another Microsoft creation. Microsoft Excel is known as one of the most well known Microsoft creations in existence today. Now the automation process allows the applications that have been written in languages such as Visual Basic to control the other applications upon the insertion of the necessary code. . there is nothing that could go wrong.84 VB Excel: Automatic is better than Manual With the good thing about Microsoft. In its easy use and user-friendly atmosphere.
but with patience and enough practice. . he can succeed in it. it is just as important for a person to understand both Visual Basic and Excel to do this automation.85 To wit.
it is a tricky sequence. where most gadgets introduced into the market are generally items that could do a lot for things for its owners. but with guides. if ever a programmer wanted to know if his string contained the symbol that he wanted to appear. to determine the strings as well as their location.86 VB Instr: Finding the String? In making the best possible computer program. And in today’s needs. In this. he would definitely have to use the InStr method. Take for example Visual Basic. Of course at first glance. as well as utilize it in as many applications. Though one of the hard points within Visual Basic is called String Position. it’s really doable. this could be mastered through practice. it is very important to have it designed in a way that the user’s could understand its functions as fast as possible. while still retaining its relatively user-friendly status. which is in turn called position. and because of this the method returns a number to the programmer. as well as Website aids. Now the InStr method uses as an integer variable. and while this string may be inside another. In this method. This is a tricky part in Visual Basic. but with books. which is also named as the InStr method. . the programmers are presented by string variables that tell them all about the position of one string from another. which is flexible enough to be used in many other programs and applications. This number ultimately signifies where the string is located. as well as example.
But for those who are just starting to do programming and are relatively “innocent” enough. For expert programmers. . In fact. for them Visual Basic will be very easy. Visual Basic 2005 is apt-enough to offer incentives for those who may want upgrades. it is advisable that they buy books about Visual Basic 2005.87 VB 2005: From Books to Incentives And though Visual Basic is considered to be an easy program to use. These benefits may be in the form “test driving” the software itself to just try it out. In fact. which is a program that is far from going into obscurity. Far from it. experienced enough in the creation of programs. it’s easier to use than the old programs and as they’re already. Visual Basic is explained as thoroughly as using them will be very easy. more or less. mastering it is another matter. these are attractive reasons. especially when considering the hours spent in discovering something any programmer with a book would’ve discovered in minutes. Books can help in a huge way. With these books. it is already a perfect way to train oneself to develop a prowess in Visual Basic. which generally revolve around the fact that Visual Basic is easier to use. it looks as if the program itself is about to go into greater heights. and while Microsoft has eventually relinquished its support for Visual Basic 6 program. as well as a great hands-on workloads or projects that’ll help in the long way to develop one’s perception and expertise in Visual Basic 2005. as well as other benefits in purchasing the upgrades.
HTML is generally known as one of the oldest and widelyused programming software. it has a far simpler way of doing things. nearly everyone knows how to speak. is still taught to students because of its functions. And with its use. and this helps in learning and using the other program codes like Visual Basic. Visual Basic is just like the improved version of the old HTML. another factor that affects the relative ease in its use is the fact that programmers generally speak in English when conversing amongst themselves so the flow of Information about Visual Basic is generally in English making VB Access as easy as possible. To think of it. Now Visual Basic’s program Codes are also set in English. HTML. which has been based by Microsoft on the HTML language. which every programmer as well as school student with computer classes on programming are already be familiar with. which makes mastery of HTML look as if mastering the basics. Visual Basic also allows the programmers to add formatting on their messages in the relatively same way as the venerable HTML does. Though. like having a far simpler syntax. which for the most part of the globe. in all its simplicity. More than one program was derived from it. and its application in Visual Basic speak wonders as to the benefits of using them.88 VB Code: Improved Form of the HTML One of the easiest aspects of Visual Basic is its use of the English language. . and these codes are a set of tags.
as it will never break the pages’ layouts being viewed and examined. which makes detecting programming mistakes easier. .89 It is also user-friendly.
Visual Basic 5. which is for the inexperienced.0 was made even easier. the Standard. On the year 1994. while creating a lot more different and additional application for a wide variety of uses. as its programming environment was relatively more user-friendly. .0. The programming speed was also improved.0 to 5. and it was in effect a better program upgrade so-to-speak. shifting from 4.0 Of the year 1992.0 was launched during the year 1998. In this. and it simply shows improvements in a lot of areas of concern. predictably for the fullpledged programmers. and soon thereafter because of the rave reviews and increasing demand from users for an improved program because of incompatibility with most computers.0 was still considered as the innovative version. as well as increasing the user’s control over his program with custom-made codes for user controls. which at that time was labeled as Visual Basic 1.90 VB Date: From 1. Microsoft first released to the buying public Visual Basic.0 was released. And at the end of the line of Visual Basic upgrades.0 was released with two versions for the public to choose from. 3. while forms soon became the foundational concepts of the class modules of the Visual Basic 4. And for general two-years lull in releasing.0.0 to 6. and Professional. It was sold to the public in 1992. 6.0 was offered to the public at 1995.0 was eventually released to the buying public. and soon it became pretty evident that the long wait was indeed wellcompensated for with the newer and innovative changes within the program itself. and while Visual Basic 4. Visual Basic 3. 2.
not to mention increases the user’s control over nearly every aspect of the host application. and some of these are MapPoint and Visio.91 VB for: Automated Applications There are many reason why Visual Basic is considered as one of the must-have computer programs. This design in programming is in fact revolutionary as it is able to expand the capabilities of earlier applications on macro programming languages like WordBasic. And this makes using them as easy as possible. and for Microsoft Office applications for 2004 it has been designed to work in tandem. . the rest is just a piece of cake. As for other programs developed by Apple for example. In this scheme of applications programmers can now create and design custom solutions using Visual Basic. Visual Basic is also able to link up with its program in order to automate it as well. All the user has to do is effectively understand how each program works and with knowledge of it. of course. the programs are in great consonance with each other that they could really work towards automation with special effort from Visual Basic. and one of these is that Visual Basic for Applications (VBA). In this. Of course. there are also other Microsoft-designed programs other than Office and some of these are also in consonance with Visual Basic. which is an integration of Visual Basic with other Microsoft Office applications like Word and Excel.
92 In a practical sense. Visual Basic can also enable the user to use data from Excel and transfer these to Word. . which saves up time and effort as Visual Basis for applications (VBA) has been designed to be as flexible as possible making it one of the jewels in Microsoft.
It doesn’t even matter if the programmer includes other lines of code to the block. will continue on with the process and as the name itself says. for as long as it is an infinite. will never end. The question lies of course in how a long block of code could continue to a looping. which will command the program to a stop. change the variable used in the condition. which creates the loop's condition to stay true. there is always a code language that extends to long texts and numbers. If he doesn’t put a command on it. And throughout this process. finally breaking the loop. . This block of programming code eventually keeps on repeating itself for as long as there is the order from the programmer in the form of “Do While”. In doing the “Do While” loop. and any deletion on any part can always affect the system. but what must be remembered is that the block of programming code must. as if doesn’t the program created would. and it will. the case for as long as its condition is true. the loop. in a way. Visual Basic moves on to continue the execution of statements as long as condition is true.93 VB Loop: True or False/Execute and Terminate As in every computer program. which is to say. the condition itself would eventually turn out false. the programmer can always solve this by pressing Ctrl+Break. When this infinite loop happens. continue on its course by becoming what programmers call an “infinite loop”.
the loop will eventually terminate itself. . Though. the condition is false. if in the beginning. there will be no execution of the program.94 and once it becomes false.
and manipulate the data enclosed on it either by numerical index or by subscripting method. At some point. Every program that we know. Arrays are such a useful feature in a programming language. Arrays in Visual Basic are by default zero-based. This means that the array’s index on the first element is defaulted to zero. control. It is for this reason that almost programming languages are relatively incorporating the array function as one of their features. The arrays used in Visual Basic are categorized into two: the linear array which is composed of one or singular dimension – known as single dimensional array – and the other one. . The multi-dimensional array is then sub-categorized into two classes: the rectangular arrays where the member of every array of dimension is being extended on the other dimension bearing the same length. Array is one of the fundamental constructs used by programmers when they would like to store. was built using the arrays. the jagged array on the other hand is a multi-dimensional array in which the length size of the declared array can variably differ. arrays help a programmer lessen the burden of thinking longer procedures to complete an action. consisting of more than one array – known as the multi-dimensional array.95 What are Arrays in VB? When you are a programmer either on an intermediate level or higher. the concept about array is one required concept that you need to understand. The use of arrays is best manifested when the program that you are creating would be compacted or shortened. one way or the other. retrieve.
96 Choosing in Between C and VB If you are a programmer. specifically the Visual Basic. Visual Basic was able to respond to this problem. With Visual Basic people can get to program as powerful as the one that was created using C but with fewer procedures and routines. the established C language known to be very powerful because of its OOP capacity or Object Oriented Programming or the Visual Basic which is gaining huge followers because of its flexibility and its COM capacity or Component Object Model? C Language according to many is a more dependable and trusted programming language because of the reliability and data integrity that it has. many people still see and think that these languages have varied strengths and weaknesses that will allow them choose which one serves well the need of the user. as time passes by and new products are being out in the market. Visual Basic on the other hand is a software that is gaining high popularity in the market due to the many features and the ease of use that it possesses. Many programmers are exhausted with highly complicated routines and procedures in order to make a program. The battle between C and Visual Basic may soon be over because of the similar platforms that these two are employing on their newest releases. This is the reason why a lot of people are turning their heads into using the Visual Basic software rather than C language. However. more and more people are shifting their interest onto the newest ones. However. . which would you rather choose to use.
Everything is a drag and drop away for them. A table is a feature where the user can place into an organized manner all of his entries making it look like more of a matrix. One of the major problems of the earlier programming languages is the difficulty in task to create a procedure called table. a hundreds of procedural calls and functions are needed in order to complete a single line data table. Unlike with the earlier programming languages.97 Manipulating DataTable Function in VB Net One of the more commonly used features in an application software is the table. This added feature of the VB Net is a milestone that a lot of other programming languages of the decade are trying to emulate. Programmers who use the VB Net are happy to experience the manner that a data table is created using VB Net. The DataTable which is a virtual representation of a series of data is allowed to be created using some of the prominent functions and properties of the VB Net. . the need to create a data table is no longer a heavy burden for most users. For this reason. the use of the table has been predominantly working like the ones that are present in any application software. the creation of a data table is never that hard and difficult. Visual Basic Net has the capability that allows us to come up with a table at an instant manner. In Visual Basic Net. This function is normally used in majority of activities. The variable types defined in the Object-Link-Embed database of the VB plus the data sets.
Microsoft developed the first VB Net Express and was formally launched as the VB Net Express 2005. In Visual basic Programming. the main features include the Edit and Continue function – this is potentially the most crucial component of VB that is not present on it – where you can potentially modify the code and resume immediately on the execution of the program.98 Exploring VB Net Express Programming is like a ladder. The VB Net Express 2008 on other hand is the offshoot of the 2005. Part of the VB Net Express 2005. there is this feature where usage of the keyword is implemented simplifying the utility in the use of the object. You will need to take the first step in order for you to successfully move up to the last step of the ladder. . Formidable in the newly added feature is the replacement of the IIF function with true ternary operator and the support for the LINQ technology and the Lambda expressions. It also contains the expression evaluation with the design time – another crucial and important feature of the VB Net Express. more and more features have been added up to make full functionality on the Visual Basic Net. Above all these. This VB Net Express 2005 comprises of modularized method of learning the fundamental and intricate things about programming in VB Net. With the VB Net 2008. there is this we call as beginner’s language. It has a step-by-step approach that allows for the learner to easily comprehend and understand the theories and concepts about how to program using VB Net Express 2005.
The functionalities of string and the way we manipulate it is very much needed in majority of software applications. formatted. when strings are applied using the VB Net language. String in VB Net are characterized basically the same as the strings in other programming languages. Any programmer would agree that learning the fundamental in and out of string manipulation and control is a solid foundation that one needs to master. be it numeric or an alphabet. .they can be concatenated. or any database software like Visual Foxpro. a lot of VB Net enthusiasts are playing it seriously when it comes to learning the varied VB Net methods and functions most especially string manipulation in VB Net. a string. For this reason. a string is a set of value that can be manipulated -. padded. Apparently. In Visual Basic Net. a programmer will not have so much problems understanding and employing it when he is familiar with any programming language such as C. A string is a variable type or method that allows a programmer to input data on the storage variable based on the classified data type – in this case. and compared. encrypt. you will then have the solid and vital skills to build strong and robust applications. C++. Should you posses the ability to efficiently utilize the VB Net functionality.99 Understanding the Strings in VB Net A programming language or a software development program normally requires a handful of variable and method types as part of their programming syntax to make sure that necessary actions are performed and done correctly. String is a combination of any character. copied.
The VBScript which comes as a preinstalled program file in every Microsoft operating system is part of the Microsoft Windows Script Technology. The purpose is to make to it possible for an HTML code to work with the DOM page. These VBscripts were actually launched in the year 1996. However.100 Dissecting the VB Scripting The Visual Basic Script or the VB Script is the Microsoft developed active scripting language that is primarily used in a Visual Basic program. . One major note. The injection of a Jscript code onto an HTML will allow for an interaction with Document Object Model page. The Visual Basic Script is very similar and closely related JScripting of the Java Script. basically being utilized by web designers and developers. To date. there are no new functionalities that are added on to the VB Script since the year of 2007. As the years go by. VBScript continue to grow and has gained so much followers. the new OS platforms that are being released are making sure that Jscripts VBScripts are compatibly read over these pre-installed browsers that come with the operating system. HTML alone cannot perform the interaction. when using the Visual Basic Script you will have to remember that the scripts are not compatibly read over a Firefox or an Opera browser. It grew rapidly that the need for enhancements and modifications were rushly felt by the inclusions and embedding of various and different features and functions. Javascripts are scripts used to inject or embed functions on a hypertext mark up language code.
how do we prevent slowing down the whole process caused by strings? You can start with using the null value or 0 instead of using the open and closed double quotes. a programmer will have so many ways on how to better handle a string. however. these are not basically for speeding up the whole process. Some programmers make full utility of the various string control functions on Visual Basic to make sure that necessary ways are being undertaken to speed up the whole process of executing the program. When a Visual Basic program starts testing and executing parts it the use open and closed double quotes slows down the process of execution. Or you can rather make an assignment of a nullstring on your variable instead of just leaving it with an open and closed double quote. So. Fortunately.101 How to Handle VB Strings Effectively What are strings in Visual Basic? A string in Visual Basic is a way to identify the kind of input that you can actually place on a variable. with Visual Basic. There are powerful ways on how a programmer can manipulate and operate the strings. For a Visual Basic programmer. . The use of the null value such as zero makes the whole process a lot expeditious. Although there are so many varieties that can be used to control the string. it is very essential that he know how to effectively handle strings on a program in order for the program to have optimal speed and eliminate potential danger and problem in the program execution.
he or she could no longer resort to requesting a CD from Microsoft. the Visual Basic that we are actually using is a further enhanced version sharing some of the more highlighted features that it possesses. but because it has the multi-platform capability to create web based applications. it is relatively older at this time because of the latest and updated versions that were released. The VB 6.0 version may have received quite a few number of drawbacks due to bugs and design errors. the visual portion of the Visual basic language was derived from the interface generator of the Ruby programming language which was combined with the Omega dbase system of the Microsoft Company. the VB 6. it has continued to soar high in the market.0 CD installers.102 Learning the Simplicity of Visual Basic 6. Now. Although.0 software.0.0 is one of the best selling versions that Visual Basic had. Microsoft has deemed it necessary to stop the production of VB 6. there are still a lot of programmers that choose to use and employ VB 6.0 has gained many followers because of the ease of use that it has. Now.0. as the VB 6.0 is reaching its sunset due to the many numbers of new and updated versions. we may find it trivial to know that the first Visual Basic language that was invented and sold in the market was actually a fusion of two important software pillars – the Ruby programming language and the Basic Language. In fact. The VB 6.0 If we are to look at the history of Visual Basic 6. Significantly. Should a user wish to make use of the VB 6. .
These codes are the building blocks of any programming language. In Visual Basic. Snippet Code for Databases is a code used for manipulating and controlling large tasks that involve records and files. . These snippet codes are fundamentally useful to Visual Basic because they can perform so many when applied in programming. The Visual Basic software is composed of more than a hundred of snippet codes and they are categorized in so many things. b. there are called snippet codes which are readily used over and over. Snippet Code for Collections is a code that is used for the creation and properly locating and sorting elements and groups of arrays. These codes can perform customizing a box or a circle to creating a code on how to send an e-mail or incorporate the use of application software in the program itself. c. Snippet Code for Crystal Reports is a code that is used for setting proper parameters for reports and how to properly configure access to data report. codes are the fundamental things that any programmer or a programming enthusiast should learn to appreciate to study and master.103 Visual Basic Codes: How to Better Understand Them In the world of programming. d. Snippet Code for Applications is a code that is used for managing processes and applications concerning consoles. The following are just some of them and where they are used for: a. This code is very functional when the program involves high volume of databases.
but these are just some of the more important ones and Visual Basic codes continue to grow and expand in number.104 There are quite a few more number of snippet codes. .
The Visual Basic Net has raised so many controversies and issues while new releases are being taken on the market. One major drawback that VB Net has been found to have possessed is the difficulty and intricacy of compiling and decompiling the Visual Basic Net source code.1. the Visual Basic Net 2003 or the VB 7. Many Visual Basic followers who have tried and used the Visual Basic Net have long time complaints and issues with the Visual Basic Net because apparently. these versions of VB Net that were released are hot topics for debate because they seem to be considered just as the other versions of the Visual Basic software. the Visual Basic 2005 Express.105 Understanding the Dominion of Visual Basic Net The Visual Basic net or the VBNET is an evolution software that came from the more popular Visual Basic implementations of Microsoft using the NET structure and framework. the Visual Basic 2005 or the VB 8 version. and the VBx or the Visual Basic 10. However. the new features of the VB Net are not working as designed and have not become at par with the Visual Basic software features.0. this aspect remains to be no longer an essential debatable point. the Visual Basic 2008 or the VB 9. VB Net converter and translator is not capable of interpreting and translating all forms of codes that the Visual Basic software can translate.0. Apparently. According to its users. The Visual Basic NET versions released as of November 2007 were classified to be the Visual Basic NET or the VB 7. .
C# and Visual Basic may tend to have more differences but their underlying structure has been captured and embedded from the same point of origin. it is only mostly because of the support of legacy embossed in the language. there are additional integral classifications that are found in C# notable of which are ulong and sbyte to name a few. with the so many similarities and differences that C# and Visual Basic has. This may sound very simple and “irrelevant” but in the world of programming. For one. . fundamental of which. a whole lifetime would not be enough to have all things covered. this kind of a more liberal syntax can sometimes bring in more danger and headaches to most programmers because this is often the source of committed errors in the program. However. In terms of the variable identifiers. The C# actually resembles Visual basic so much. but incidentally. the C# allows multiple lines when putting comments whereas the Visual Basic does not. This characteristic may sound good to some.106 How are C# and VB Different and Similar? When one would freely discuss about C# and Visual Basic. in fact. While the Visual Basic software allows for shortcut in syntax when C# does not. There are a lot of things that C# has on it that Visual Basic does not have. comments play so vital in the structure. as these two programs continue to evolve. one compiled manuscript would be enough to suffice it. separate identities have been sharply developed.the BASIC language. The structure of the Visual Basic software was lifted from the very origin of C# -.
Along with the arraylist. More to that.107 How Effective and Efficient VB Net ArrayLists are? When talks about efficiency and effectiveness of a programming language. an arraylist can generally provide a collection of different and varied functions that can perform numerous functions. The powerful feature of arraylist is effectively and efficiently added on many programming languages and is found to functioning perfectly with VB Net. it is tantamount to asking the question as to how broad and powerful the functions and features that a programming language has. manipulate. thus suited for many and diverse uses. A collection feature allows a programmer to control. there is what we call as class. and delete entities or objects from the list of array. . Logically. An arraylist is a pictorial representation of a huge and dynamic sized and index based collection of entities and objects. a class can be best represented by a group of people that are combined and collected together to perform a specific function. A class will allow any programmer to perfectly add. embed. VB Net Arraylist is one function that will allow a programmer to do and perform collection. As effective programmer. One of the more dominant and useful feature that programmers look into a language is the capability of it to make full utility of collections in a program. he or she must be able to come up with varied plans in order to perform an action. Visual Basic Net as a programming language is fully aware of the need that a programmer requires. and manage several groups of entities or objects.
minute and so many others. There are systems or programs that basically require the use of the systems clock but apparently. As for the method to be used. the operating system’s clock has its own platform to follow thus make it difficult for the programmers to easily “borrow” the system clock and embed it on the program. These properties will then require the exact method to employ to make sure that the correct and precise attribute will appear on the program. month. The date method in VB Net will allow for the programmer to determine and complement the date and time of the system onto the program itself.108 Working on the Method called VB Net Date Generally of programs that are created involve the use of the date and time method. or add hours to add specific hours to the date property. To potentially resolve this. the makers of the VB Net has come up with the Date function that will allow for the date. Some of the properties that VB Net Date use are day of year property. . the VB Net has thought about including on the VB Net date attributes so many time and day bound attributes to serve the purposes and needs of the users. time. time of day. day. and day attributes of the systems be utilized in consonance with the program. The Date method of the VB Net generally allows for a programmer to have an instant time and day onto its program when this structure is employed. the following can be employed: add a day if you wish to perform an action of adding the value of the specific time span to the date value. To make it more functional. hours.
Although admittedly. .109 A Method Called VB Net Split In programming. there are a hundreds of thousands of ways that you can use for a particular action to be performed. The VB Net developers have potentially seen the powerful use of this method to a lot of programmers. some of these should need further digging and researching before you can finally realize their existence. it shall be made readily available. there is a variable method that a lot of programmers are keen to using at. There will be an instance in your programming career when you will be faced with a problem on how to separate a single line of strings into a particular number of lines of texts. This string method is capable of allowing a user to slice a series or lines of text strings and place each entity into another method – the array. the ability of the programming language to perform a seemingly impossible action is beyond reach. In VB net. This method of variable is termed as the VB Net Split. Separating each string would then mean splitting the line of text into different lines. still. However. The solution to this kind of a problem is to employ the Split method in the VB Net.an extended feature that works similarly like the split. It is for this reason that they have come up and developed the Enhanced VB Net Split variable method . This is quite simple for an idea and truly very simple to encode. by separating it. you will need to make sure that each entity is properly secured and stored so that anytime the program will be calling on the next entity.
People who are experts in the field and people who are merely enthusiasts share knowledge and insights about topics that revolve. Threads or forum threads are some of the exceptional sources of information and the more up-to-date ones. There are people who merely post and shout a specific question or inquiry and from there a thread will evolve. With these threads. you can actually learn and adapt new techniques about to better program using the VB platform. There are threads or forums which are privately owned and there are some which are not. Although. of course with Visual Basic net. the whole concept of the thread is geared towards effective dissemination of information to all who are directly or indirectly impacted. there are information that seemingly are irrelevantly posted due to mismanaged monitoring. but nevertheless. But what is important about these threads is the fact that they are enormous repositories of quality and excellent information. . I would say that these are potentially useful sites for people to use. As a thread user. There are designated people who monitor and maintain a thread and there are some threads which are being maintained by the mother site.110 VB Net Thread: A Good Source of Information and Updates Just when you thought you need more and more information and updates about Visual Basic Net and you thought about running thru the site threads that are scattered all over the net. Tied-up answers to the questions begin to come out until a common knowledge is achieved out of the concepts and insights provided. Threads are all over the Internet.
Its primary applications are focused in relational database management systems or commonly termed as RDBMS. Schema Creation and Manipulation. . with the looks of it. The SQL will allow for the programmer to effectively control and manipulate all database related functions and procedures. When you link Structured Query Language with Visual Basic. Standard Query Language in itself is a known powerful database query manager language that a lot of database programmers have enjoyed using and applying in most of their programming stints. The integrated development environment that Visual Basic possesses becomes the interface for both the SQL and the VB functions to happen all at the same time. you could just imagine how unimaginable the power of Structured Query Language is. the features are just ultimately superimposed. While the SQL is at full force working its way towards effectively manipulating the database. Now.111 VB SQL and its underlying prowess It is quite unimaginable having to combine two of the most powerful methods in a single function – Standard/Structured Query Language and Visual Basic. Having all these mentioned and said. SQL as a database software has an unequalled power in terms of database management and control. when you combine these powers of SQL with Visual Basic. However. looking into it deeper. there is a greater amount of simplifying the procedures that will make use of the database applications. these two have indeed been fused and amalgamated into a single function – the VB SQL. the Visual Basic language on the other hand allows for the right “portal” for all these things to happen. and dbase object and access control management.
The P-code is the code that is being translated or interpreted virtually by the machine that results into a more portable code and potentially smaller code file size. that so many fearful speculations about the very sensational Y2K virus have been ramping up in all IT enthusiasts. The Visual Basic 6 is an offshoot of the Visual Basic 5 version. It was in 1998. More to the feature of the 6. Although the Visual Basic 6 is a newer version. The drawback of the P-code is rather tolerable but the P-code primarily slows down the executing process because there is an added layer of code that is needed to be interpreted or translated.0 is known to have missed this very essential feature that a lot of version 6 users have found to be incredibly hot and functional. Some of the more notable improvement that VB 6 has is the capability of the 6 version to create and develop applications that are web-based by nature.0 it has the capability of interpreting and compiling the source code into either the native compilation mode or in what was the previous versions are doing the Pseudo code. it still manifests the primary characteristics of all the other versions of Visual Basic. . Its underlying facet is still anchored from ease and relevance in use. There have been quite a number of improvements that were potentially seen on the newer version.112 Visual Basic 6: What is it? The Visual Basic 6 has come into existence in the middle part of the year 1998 when the information technology was at the verge of its being over hyped. The prior version. the version 5.
made it possible for the VB users to create executable files that are necessary to easily launch a software. there is a more simplified and clarified source code building in the 2005 version of Visual Basic employing new and clearer keywords on it. more Active X controls which is becoming the real trend in programming. These ActiveX controls. The new Visual Basic 2005 has been predominantly used by many software developers because of the capability of this to catch and use the Active X controls feature. the Visual Basic 2005 finally came out in the market. although present in the other version of the VB versions. the Visual Basic software evolved into what it is right now for Microsoft’s Component Object Model programming – a well designed standard of interface for Microsoft’s software components. It was in 1991 that the term Visual Basic was formally used to coin the term that we know right now. Primary of the new features is the newly enhanced IDE or Integrated Development Environment that it has where added VB functions and easier interfaces have been integrated into the new package of VB 2005. Visual Basic 2005 has many new features to offer. In addition.113 Visual Basic 2005 and its Evolution Visual Basis or VB is a programming software that was developed and manufactured by the world’s leader in software solutions – the Microsoft. . Visual Basic 2005 is an offshoot of the many Visual Basic versions beginning with the very first created one known as the Thunder. After years of releasing the other versions of the Visual Basic Programming language. and incorporate more DLLs or dynamic link libraries. Purposively.
The foundation that you have on your BASIC . Primarily. As for the device. it would be a lot easier for you to create a program using the VB Express. the mere fact that this VB version is able to help so many neophytes in the field of programming. Windows NT. Microsoft saw this event as a way to help other people by building the super easy to learn programming software. This has brought so many people’s interest into programming and software development. The concept of the Visual basic Express is anchored from the event that transpired way back. When you have enough background in BASIC programming. While for many people. and Windows Vista. Visual Basic Express is deemed fundamentally basic and primary.114 Visual Basic Express: Learning it fast and easy The domination of engineering software has evolved fully and was critically highlighted during the time when the 2000 virus that threatened the whole world of potential computer shutdown was exaggeratedly being discussed and debated. it can work on some of the major released operating systems provided for by Microsoft such as the Windows XP SP2. The Visual Basic Express is a software that was designed to work with several platforms of operating systems and devices. Windows 2000. people have an easy way to learn and understand programming. With the Visual Basic Express. as long as you can install and run the compatible operating system. then it is by no means to be called as fundamental and basic. then the software – Visual Basic Express – can then be downloaded and installed on the device.
115 programming can help you lessen the burden of familiarizing yourself with the basic constructs in programming. .
the mere fact that their objective lies on the same perspective. At some point.116 The Jeopardy of a Worm VB In the world of information technology. The VB Worm although identified by its name as worm type is actually a worm. A PC worm differs in the manner they infect a PC resource because a worm does not a host in order for it destroy. Although these two menaces of the PC may have varying ways on how they populate and “grow”. Although. The Worm VB is known worm type that basically infests and destroys visual basic files and programs. Worm VB has been discovered to be infesting some users in the first quarter of the year 2007. the capacity to infect and destroy PC resources is relatively low. on the other hand. A worm is by no means different with a virus because a worm is being created to potentially harm the PC resources just like the virus. A virus. the Worm VB is taking the alias of F-Secure or Kaspersky or Grisoft. it is in fact more likely to be characterizing the virus type. . the industry has been plagued for the longest time with problems and issues that concern malicious destruction caused by a worm. though. requires a host file and piggybacks from the host and can only start destroying PC resources when the host has been activated where it is piggybacked. it is still considered as one of the more celebrated worm names in the year 2007. In some instances. these two then are basically the same. A computer worm is a highly technical term that most often people do not understand clearly.
thus the Visual basic express for kids course is offered. Covering these 10 chapters will teach the kids to learn how to build a VB Express Windows application. Various VB Express editions are designed and made available for people attempting to learn programming language. This course mainly serves as an introduction to computer programming among kids enabling them to gain an interactive and self-paced learning of a new Visual Basic Express programming atmosphere. toolbox. is when VB Express has been principally developed for kids’ learning. Specifically. project designing. a card game. The Visual basic Express for kids course is intently designed and offered to be understandable among kids with age range of 10 and up.117 Reinforcing kids’ visual interest and skills through VB Express tutorial course Visual basic (VB) Express was initially developed particularly among beginners in computer programming. such as a drawing program. There is certainly no programming expertise . and other more elements of basic computer programming language. guessing game. Students will be learning about VB Express menus items. A notable progress however. Various fun activities. which are written in simple and easy-to-follow terms. Tic-Tac-Toe. and other simpler video games are also included. the Visual basic Express for kids tutorial include discussion of 10 chapters. This VB Express tutorial for kids attempt to help out kids learn how to use the basic concepts and principles of VB Express to create Windows applications. Each VB Express version would have its distinct features compared to other available editions.
unlimited access for support. However. The Visual basic Express for kids currently sells around US$20. Taking up the full course would include a course fee.00 with additional promo items included .118 level nor experience required. and consultation via e-mail. kids should be at least familiar with some common tasks carried out when using Windows.
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Understanding the concept of VB class
Visual basic (VB) is an event-driven programming language that uses the Microsoft Windows platform. It is an objectorient application development wherein all involved procedures are called automatically when an end user clicks the mouse, selects menu items, moves objects on the screen, and others more. Visual basic essentially serves as a tool, which enables a certain user to create windows with elements (e.g., text boxes, list boxes, menus, command and option buttons, scroll bars, etc.). Moreover, a visual basic makes use of graphical user interface (GUI) in creating these particular programs or applications. GUI is used to create powerful and robust programs or applications. This user interface specifically uses illustrations for text that enables a user to work with an application. The GUI feature makes possible an easier and quicker comprehension or understanding of things. One of the integral components of an entire programming language is a VB class. It is the formal characterization of an object and the template from which an example of an object is created. The class is mainly created to defined properties and methods. Moreover, a VB class is best explained by three significant concepts. These three important concepts include: (1) a subclass capable of inheriting some, if not all of a class characteristics, (2) a subclass that is also capable to defining its own methods and variables not part of the parent class, and (3) class hierarchy, which involves a class structure and its subsclasses.
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Lastly, a single class entails a lot of terminology. Initially, a VB class can be identified either by equivalent names, such as a parent class, superclass, or base class. A new class could either way have child class or subclass as names.
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What is a VB format?
Visual basic (VB) is defined as a third-generation eventdriven programming language that uses the Microsoft Windows platform. All programs that are produced using Visual Basic would appear and function like customary Windows programs. Visual basic uses GUI in creating these particular programs or applications. A graphical user interface (GUI) is used in creating these powerful and robust programs or applications. The GUI specifically uses illustrations for text, which allows a user to interact or work with an application. This GUI feature enables easier and quicker comprehension or understanding of things. Generally, visual basic serves as a tool, which enables a certain user to create windows with elements, such as text boxes, list boxes, menus, command and option buttons, scroll bars, among others. It essentially applies a standard format particularly in formatting user-defined styles or output. The customary format is: Format(number, "user's format"). For instance, a format(1234.5,"0") indicates rounded off numbers to a whole number thus an output equivalent to 1234. On the other hand, a format(0.657,"0.0%") signifies that numbers are converted to percentage with decimal places therefore a 65.7% equivalent output. A format(12345.6789,"#,##0.00") signifies rounded off numbers to two decimal places with separators between thousands, which is an equivalent output of 12,345.68. Lastly, a Format(12345.6789,"$#,##0.00") indicates a dollar sign shown and rounded off numbers to two decimal places with separators between thousands therefore a $12,345.68 equivalent output.
). ..122 In general. etc. Specifically. rounded. converted. a format in visual basic is a significant function that is used in formatting customized output or styles.g. A visual basic (VB) format mainly provides a standard format for every set of used numbers (e. a format basically provides structure of a layout or style.
such as OLE (Object linking and embedding). Lastly. This process basically allows communications between dynamic objects. on the other hand. which are core concept in OOP (Objectoriented programming). OLE is a Microsoft owned standard distributed object system that handles compound documents and transmit data among applications through copy/cut and paste. Specifically. and . which are AddRef. is used in describing the connection between significant elements.) Lastly. and drag and drop techniques.. which was created by Microsoft. DCOM. IUnknown particularly defines its three functions.g. IUnknown is the basic interface in a COM’s case. the occurring communications is resulted or created in any specified programming language that supports VB COM. in the context of a software development jargon. OLE automation. ActiveX or ActiveX Data Objects (ADO) is an API (Application Programming Interface) founded on OLE DB technology. The COM. mail messages. Apparently.123 VB COM: Define The Visual basic (VB) Component object model (COM) is defined as a Microsoft integrated software platform that was developed and has been around since 1993. Release. Access database. and ActiveX. interfaces. ActiveX essentially facilitates access of data from various data formats (e. is a series of Microsoft concepts and program interfaces by which a client program object can call for services from another computer’s server program object in an active network. various SQL supporting databases. serve as the COM’s central model. clipboard. etc. Interfaces also represent the design by contract principle. DCOM (Distributed component object model) technology. COM+. COM+ is fundamentally an extension of COM. Word documents.
124 QueryInterface. The QueryInterface. . in contrast. the AddRef and Release are responsible in controlling the reference count of a certain COM object. Among these three functions. enables the end user to discover other possible interfaces that a given object carries out.
.. If VB finds an accurate “Case Else” statement or a match for that matter. the user may test each statement on whether a condition that is being considered: (1) can either be true or false. (2) has various values of an expression. or (3) has various exceptions that are generated.. whereas the “Select” statement is used in evaluating a single expression only once and for every comparison that is carried out. Thus.Then. The “Select…Case” statements can essentially be used as an option to the “If.. VB can execute the respective code adhering to the “End Select” statement. the “Select…Case” is used to evaluate performance rating approved through Function method. The “If” and “ElseIf” statements can be used to evaluate a different expression in each statement. were carried out. A “Case” statement can include either multiple values. At any rate. any number of “Case” statements may be acquired with either an inclusion or omission of a “Case Else” statement. Concluding with an example. Specifically. VB significantly compares the values in the “Case” statements over the value of the expression according to the sequence that they appear in the “Select…Case” block. a range of . “the Select…Case” statements is among the decision statements supported by Visual basic. it then carries out a parallel statement block.125 Making the most of VB Selec Case statements Visual basic (VB) basically enables any end user to test certain conditions and carry out various operations based on whatever test results are achieved.Else” statements when comparing similar expression to several distinct values. When a series of statements for instance.
So when a “Case” statement therefore contains multiple values. these consequently results for the “Case” block to be carried out if any of the matched values are that of the “Select” statement expression. or a combination with operators’ assessment. .126 values.
Take the commands in Visual Basic as an example.127 VB Function: Essential as a Business Language If there is one programming language which is preferred both by programmers and business owners the world over. . intermediate up to the advanced level of Visual Basic. Else. Now. depending on what you would like the program to do. let us take a look at some of the basics for this programming language. Then. Select and Goto. you can buy a book which can serve as a complete beginner’s guide to the programming language – or you can enroll in a short course for the beginner. Creating a program for efficiently running the financial aspect of your business is another application of Visual Basic as a programming language. you can use Visual Basic as the language to create an accounting or inventory software for your business. For example. It includes words like If. the reason why Visual Basic is the programming language of choice for business applications is because it is the one which is more comparable to human language. that is none other than Visual Basic. there is an organized list of instructions which result to the computer ‘behaving’ in a particular manner – and the set of instructions is the programming language that the computer understands. it is pretty easy to study when you are supposed to use these commands. Before delving deeper into the functions that you need to learn about in Visual Basic. For any beginner. To learn more about Visual Basic. In any type of computer program.
in order for you to get a head start at programming. Now. you need to learn about the good codes and formats used in Visual Basic. here is a quick overview of the steps that you can follow: . There is no need for you to worry.128 One of the Best Applications of Visual Basic: VB Games What is the sense of having a computer if you will not be able to play games? Computer programming may sound ‘nerdy’ or ‘geeky’ to those who do not understand the programming language – but there is a fun side to it – which comes in the form of games creation. First. though. because Visual Basic is a language which is closest to the one that we use as humans – so it is quite easy to understand. for the process of the game creation itself. In Advanced Visual Basic. the more advanced functions and more complicated commands in order for you to create a computer game. here are a few things that you need to understand about this programming language. Before delving deeper into the heart of computer games creation using Visual Basic. Second. . . you will learn about API’s.Create a plan on how you can execute your idea for a computer program.Create a storyline based from your idea of what a fun and exciting computer game should be. One of the best programming languages to use when creating computer games is Visual Basic. you need to learn about the basic Visual Basic commands if you want to advance to the games creation level.
the characters and the other aspects of the computer game. use Visual Basic game programming in order to create your original computer game.Make a list of the details about the storyline. . .129 .Finally.
. . the interface is user-friendly and you can practically create any type of program using Visual Basic. delete. For programmers. class refers to a ‘container’ for data and code or methods – which can be accessed with properties. then move on to commands. No matter which . Classes in Visual Basic can be used for the following: . In Visual Basic. in order for your Visual Basic programming skill to improve. you may already know that several versions of the original programming language issued by Microsoft have evolved over the years.To add. For those who are familiar with Visual Basic.To read. write and index the lines of text within a file. All in all. API’s and the more advanced applications. edit or retrieve date when wrapping up a presentation. the first thing that they need to learn about is how to write good codes.To wrap up the ‘global variables’ within a program so that the properties within a class can be combined. For beginners who would like to familiarize themselves with Visual Basic. Now. This is one of the many methods of designing and creating a software using Visual Basic. Visual Basic is what most of them prefer because it easily resembles the human language. formats. you also need to learn about object-oriented programming. This is where class comes in. a language is only as good as its latest version. using classes in Visual Basic to create a line class is a more efficient approach to programming.130 Visual Basic: What You Need to Know about VB Net Class In the world of computer programming.
.131 version of the Visual Basic it is that you will use – you need to learn about the basic terms like class. functions and properties in order to familiarize yourself with this programming language.
Aside from functions and procedures. Visual Basic is quite easy to learn due to the fact that it is the one closest to the human language. They can either be executed independently.132 The ABC’s of Visual Basic. This means that the environment in Visual Basic is more user-friendly. no matter what type of application you will be using the program for – you can easily create a program for yourself using the knowledge that you have gained about the Visual Basic programming language. There are several reasons why this is so. Second. each with their own programs codes. there are two ways that functions can be used: without a parameter or within a parameter. First. In this type of programming language. As compared to procedures in Visual Basic. you can move on to the intermediate and advanced level of the Visual Basic programming language. . Visual Basic is composed of subprograms. Visual Basic is executed in a graphical manner. you need to learn about functions. Finally. you should also learn how to write good codes and formats and you should familiarize yourself with the basic commands. you can use the Visual Basic language to create almost any program for a wide array of applications. Unlike the BASIC programming wherein a text-only program is executed according to sequence. the primary purpose of functions is to return a value. VB Functions & VB Applications Visual Basic is one of the most preferred programming languages in the computer world. after studying the basics. Once you have gotten started in creating a program in Visual Basic. or linked together to create the type of program that you need. Third. With this.
you will be more comfortable using VB. what exactly is Visual Basic? For the uninitiated. Visual Basic has spawned a number of advanced versions of this programming language.0.Net.Net C#? Just like any other programming language. you will be better off using the Visual C#.Net. if you have previously been working with Visual Basic 6. these two are both top of the line. For most programmers. First. Here.Net includes more powerful features.Net and Visual C#.133 What is the Main Difference between Visual Basic’s VB. they all have one predecessor which is the Visual Basic program. including Visual Basic. Visual Basic is their preferred programming language due to the fact that it is the one which closely resembles the human language. When it comes to being a firstclass programming language.Net and VB. the way that the language is created leans more towards what the programmer is already familiar with.Net environment. if you have been previously working with C++ and Java applications. Despite the fact that different versions are available. These two can be considered as similar because they are both based on the framework of Microsoft which is the Microsoft.Net C#.Net. we will try to differentiate Visual Basic’s VB.Net and VB. The only difference between the two is that Visual C#. the interface is user-friendly and more complicated programs are still quite easy to create. Over the years. As a rule of thumb. . this is a type of programming language which evolved from BASIC or the Beginner’s All Purpose Symbolic Instruction Code. On the other hand. there are different versions of Visual Basic. Additionally.
NET can be viewed as an evolution of Visual Basic. Though improvements have been made. If C# is a procedural objectoriented syntax based on C++. As for language translators. but then again it would be best to learn the basic principles behind each to be able to apply both in creating software programs. To learn the basics. others resort to a free online tool provided by various sites known as “language translator”. The exact same thought not only happens with foreign languages but with programming languages as well. VB. the main difference lies on syntax usage. there are a lot of web sites that offer such service and it would be best to check its accuracy first before using it in software programming.NET were developed by Microsoft.NET It is not that easy to learn to speak new languages other than your own. The passion to embrace foreign languages gives one an insight of the nation’s rich cultural background. aside from enhancing one’s own communication skills. Both have their own advantages and a translator would be of great help to fully understand each language better. . while others prefer to visit the country personally.134 The Ease of Converting C# to VB. wherein the user can put in a word or group of words on the field provided and select the language translation preference to display its language counterpart. Choosing either one of these two programming languages is a matter of personal preference. There are some who opt to study in prestigious universities to learn how to speak foreign languages. Though both C# and VB. Take for instance C# and VB. programmers who are familiar with C++ and VB will not find it difficult to get familiar with the new codes.NET. Syntax means statements and language elements.
but the need to focus on redevelopment efforts in converting the system from VB6 to VB.NET program for free. still developer dissatisfaction is very obvious.NET. Downloadable converters were made available.NET easier. which is Visual Basic . VB programs that are algorithmic in nature are easier to migrate. But then again. the main concern is not about the enhanced features of VB. the big switch still became controversial. It is because of these not so favorable remarks from programmers that made Microsoft decided to release an automated VB6 to VB.NET Microsoft’s decision to sunset Visual Basic 6 and move to its designated successor. database support and on implementation details is very challenging. There are also some web sites that offer downloading of the VB. However. However. but converting features such as graphics.NET.NET stated that the new language is more powerful and easy to use than the original. and neglect the original version that programmers have learned to adapt over time. unmanaged operations.135 The Need to Download and Upgrade to VB.NET framework paves the way for the improvement of a lot of VB functions. . It is more of like forcing oneself to embrace something new. has made a lot of programmers upset. Proponents of VB. there are also other sites that made the conversion from VB6 to VB. Though developers have found a way to convert some of these features over time. Aside from Microsoft. the problem is that this does not include all codes. together with software updates to optimize the developer’s programming experience.NET converter. Though the strategy to move to a .NET. either for free or for a premium cost.
136 make sure that these downloadable software applications are free from malwares as this can definitely do more harm than good. .
There are also some that offers programming languages with enhanced user interface. .137 Visual Basic Tutorials for Free For full-pledged programmers. Visual Basic is one of the most widely used programs then. it is very easy to learn new programming languages to be used in software development. Definitely. BASIC and C. This encompasses such languages like Assembly. it would take time to master such programming skill and it would be best to familiarize oneself with one programming language first to just get the hang of it. using syntax and codes to create a very complicated software program. VB6 is the latest version of Visual Basic and there are also a lot of free tutorials that can be found on the web to help one in understanding better its user codes. learning prehistoric programming languages is required. syntaxes and functionalities. Check on these web sites and discover the world of software programming made easier through Visual Basic. before Microsoft had decided to migrate VB users to the . and journals are already made available on the Internet. Now that a lot of free training materials such as tutorials. it is still a good training ground for beginners in the field of programming. while some can be downloaded for free. As for beginners. Some tutorials can be read online. In most computer universities and colleges. Though Visual Basic is already considered an old programming language. wherein users have to be acquainted with MS DOS. it is but wise to take advantage of these resources.NET framework. it takes one to have a very analytical mind to understand the ins and outs of programming. such as Visual FoxPro and Visual Basic.
But then again.138 The Basics of Microsoft Visual Basic (VB) In the challenging world of programming. Visual Basic is known as a programming language that is very easy to learn and use. and (d) Strong integration with the Windows Operating System. As technology progresses. (b) Bitwise and logical operators are unified. Aside from allowing users to create simple GUI applications. Visual Basic . and rapid application development (RAD) of graphical user interface applications or GUI. Some of the characteristics of VB that makes it different from other programming languages such as C include: (a) Boolean data type is stored as a 16-bit signed integer. VB has undoubtedly paved the way for the creation of . it can also be used to develop complex applications by visually arranging components and controls on a form. creation of Active X objects and controls. specifying actions and attributes of such components and writing additional codes for more functionality. Such traits of VB made performance problems experienced by some users have become less of an issue. Developed by Microsoft. (c) Variable array base. there is one language that has undisputedly laid the foundation of software development and this is known as Visual Basic or VB. VB is considered as a third generation event-driven programming language derived from BASIC as it enables access to databases such as ADO.NET. still VB remains as a good training ground from beginners in enhancing their software programming skills. it is but inevitable to also make improvements on the different tools used in programming. RDO or DAO. Though Microsoft has already discontinued supporting VB in February of 2008 and forced the migration of developers to its designated successor.
139 fantastic software applications in the past that can be used as reference for tomorrow’s software era. .
This update was made in reference to Microsoft’s decision to drop “. The third generation of VB. Microsoft’s announcement to discontinue the use of Visual Basic has spurred a lot of controversies but many have come to accept this fact as time passes by. Breakthroughs in technology were made possible through constant planning and research from key people of today’s big industries. In effect. (d) Improvements to the VB to VB.NET released as of November 2007. Visual Basic . All of these features were incorporated to the software in aid to reinforce VB.NET converter. . and (f) Data source binding. If Visual Basic is OUT.NET”.140 Understanding Microsoft Visual Basic 2005 As the quest for new and innovative products intensifies. (e) The use of USING and JUST MY CODE keywords. The same thing happened in the world of software programming. a lot of tools were also enhanced to cope up with the demands of the growing market. The release of Microsoft Visual Basic 2005 has also made more improvements to the software such as (a) Edit and Continue feature. (b) Design time express evaluation. as they record and anticipate all possible threats to come up with a close-to-perfect product.NET’s efforts to differentiate it from the C# language.NET programs is called Microsoft Visual Basic 2005. there are already four versions of VB. (c) the My pseudo-namespace.NET is IN. A brilliant mind is always associated with state-of-the-art tools and mechanisms hence various improvements to such applications were also incorporated.
0 converter to further evaluate the feasibility of converting from older versions of Visual Basic. . It contains Visual Basic 6. This software is a must-have for beginners as it is specifically intended for users who are just learning the language.141 Microsoft also released a free development application called Visual Basic 2005 Express.
0. (e) To take advantage of developer productivity improvements.NET was made more convenient through software converters such as the Visual .NET Imagine that you are in the process of completing a project using a particular software and half way through your boss tells you to use another software instead. the . The smooth transition from VB 6. The same thing happened with software developers who got used to Microsoft Visual Basic 6. unless your boss changes his mind once again to your favor. programmers have expressed their dismay and are worried on how to convert their projects to the new system. As specified by Microsoft. (f) To ensure on-going official support.NET. After Microsoft had announced its decision to stop supporting VB 6. (d) To improve the maintenance of an application.0 to . (c) To consolidate company’s software assets.NET framework. Actually.NET platform: (a) To web-enable the application and enhance its existing features using VB. here are some of the reasons why there is a need to upgrade applications to VB. all of a sudden it will be put into waste as you have to redo everything using a different software.142 The Need to Upgrade Software Applications from Microsoft Visual Basic 6.0 to . Visual Basic Studio .0 and introduced Visual Basic .NET.NET.NET and ASP. the only option you have is to accept this unfortunate incident. (b) To lessen the cost of on-going business activity. This is indeed very frustrating that after you have checked the details of the project.
143 Basic Upgrade Wizard. . not all applications should be upgraded such as those with short expected lifespan. But then again. Applications that can create a huge impact to the business are the only ones eligible for the software upgrade.
(d) a reliable developer experience across a wide range of applications.NET a chance is to prove its worth is something that software developers have to take into consideration. robust debugging tools.NET framework is not that bad after all. (c) safe execution of codes. easy methods of reusing codes. it is still a good indication of progress. and memory leak monitoring. At first. A very good example is Microsoft’s decision to discontinue VB 6 that most developers have been using through the years and introduce Visual Basic . and (e) communication protocols on industry standards. Given such case. Come to think of it. the choice to switch to a . as this depends on how the person sees things.NET.144 The Transition to .NET Framework from VB 6 In this world where everything is subjected to change. Though learning something new is a challenge to everyone. but it is the person’s willingness to accept change that makes life less complicated. . there is a need to be flexible. The road to success may be bumpy and rocky at times.NET. Some of its objectives include (a) a programming environment that is consistently object-oriented in nature. the affected people find it hard to accept that VB 6 will be out of the picture and so there is a need to undergo migration to VB. creative and optimistic in order to move on from an unexpected incident. (b) simple software deployment coupled with minimal versioning conflicts.NET. Such aims resulted to the integration of additional features to VB 6 that include seamless deployment. Change can either be good or bad. Giving VB. it is the prerogative of the developer on how he or she can strategize in adapting VB.
An easier to use version with improved speed was released in November of 1992. payroll systems. Visual Basic 1. Not only that software systems change but also software programs need to be consistently enhanced to incorporate more features and functionalities. also known as Visual Basic 2. One of the most widely used programming languages in the 90’s era is Microsoft Visual Basic.0 was released in May 1991 while its DOS version was released in September of 1992.0 – The Visual Basic Software Evolution The brilliant idea of developing software programs to create software applications has opened a lot of opportunities for people to apply their creativity and willingness to initiate changes to the old system. The establishment of inventory systems.0 in the summer of 1993.0. In February 1997. and testing systems has initiated innovations in completing work loads faster and more convenient. Creating 32bit and 16-bit Windows programs was made possible through Visual Basic 4. . Microsoft released Visual Basic 5.0 that is exclusively for 32-bit versions of Windows.0 to VB 6.0 released in August 1995. The huge demand to automate processes using computers has definitely wiped out the manual work of maintaining records little by little.145 From VB 1. Its first version. Standard and professional versions of the software were released as Visual Basic 3. It also introduced the creation of custom user controls. The interface used the COW (Character Oriented Windows) interface. using extended ASCII characters to simulate the appearance of a graphical user interface or GUI.
0 and has introduced a lot of improvements such as the ability to create web-based applications.NET. . wherein developers were asked to use Visual Basic .146 It was on mid-1998 when Microsoft introduced Visual Basic 6. Microsoft stopped supporting the program in March 2008. VB6’s designated successor. However.
Most API’s that take numeric arguments only expect 32-bit values but VB.NET will not work with 32-bit API calls.NET converters but a lot of negative feedback was generated from programmers who are having difficulties completing the migration process. which are only available in a particular programming language and “languageindependent”.0 anymore. The process of declaring Windows API using Visual Basic has changed when Microsoft opted not to support VB 6. Its compatibility with Windows API is yet to be proven. iPhone API. MediaWiki API. and Windows API.0 to VB. Microsoft has provided VB 6.NET is one of the main priorities of Microsoft with the VBRun web site as its latest offering that makes it possible to integrate VB 6.NET has made a lot of developers upset about the need for application migration. There is a discrepancy on this area as VB. The release of VB. The use of Windows API is common to software programmers through Visual Basic (VB).NET solutions.NET will only work on 64-bits. Some of the wellknown APIs include Google Maps API. Youtube API. though doing so will require external function declarations.0 and VB.147 Using Windows API in Visual Basic (VB) An API (application programming interface) is a source code interface that an operating system.0 to VB. Some claims that other codes were not recognized and there is a need to manually work on them. Shifting existing codebases from VB 6. . Java Platform Standard Edition API. there is a need to change the parameters into integer data type to invoke APIs. It can either be “language-dependent”. service or library provides for the purpose of supporting requests made by computer programs. For this reason. which are written in such a way that they can be called from several programming languages.
Some of the array data types include integer and string. 8. which is referred to as a set of values that are logically related to each other. One of these terms is array. These related values are called index or subscript whereas an individual value is called the elements of the array. 2. which means that this array always remains the same size. Array size starts at 0 so if 11 is declared as the array size. this means that it actually holds 12 elements (0. On the other hand. 3. you will encounter a lot of terms and codes that you will use in creating software applications. specific tasks can be performed such as sorting array items in alphabetical or numerical order. passing the group of items as a parameter to a VB function. or accessing and changing the value assigned to each array item. the DIM keyword is being used.148 Learning VB Arrays In Visual Basic. while size value enclosed with parentheses defines the array’s maximum size. 1. which means that its size can change at run-time. Learning to use arrays is one of the basics of learning Visual Basic. 4. There are two basic types of Visual Basic arrays. The syntax then would be: Dim arrayname(size) As dataType Arrayname refers to the name by which the array will referenced in code. the dataType value is actually the type of variable that the array will hold. 6. Once variable values of the same type were grouped together. To declare a Visual Basic array. One is called a fixed-size array. 5. It is therefore recommended to read a good VB book or . The other one is called a dynamic array. 9. 10 and 11). 7.
149 access VB tutorials on the web to get familiarized with arrays and other VB terms and concepts. .
This action might not be possible to undo. Are you sure you want to continue? | https://www.scribd.com/doc/20679123/Visual-Basic-100-Success-Secrets-VB-100-Most-Asked-Questions-The-Missing-Visual-Basic-Reference-Guide | CC-MAIN-2015-48 | refinedweb | 29,121 | 58.48 |
Hello,)."
It would be much easier to use the ListTables() function.
The same script with import feature classes from one geodatabase to another (FeatureClassToGeodatabase_conversion), works correct.
OK, but I would like to import not all tables from source geodatabase (only Table_A and Table_B). I'm not interested in Table_C .
Thanks for help.
This can be done easily with an if test. For example, "if table != 'Table_C:'"
This will exclude Table_C
Replace that line in Caleb's code, will that work --- substituting one list for a more limited list. Give Caleb credit, if you will.
EDIT: Hello Caleb - you get at least a point on that 1st bit about ListTables, all in the same line with the string filter. Just for the 'clean-appeal'.
Even better :)
I'm curious why my solution does not work? :)
Is it possible to use txt file?
source= r'C:\\Data\Data.gdb'
Also, if in doubt print it out.... promise you I didn't mean for the word play...but check it with a print statement. Reversing the '\\' to '//' I think is standard, but when my eyes are fatigued at the end of the day, that's is certain to irritate me to discover that I forgot one of those. Use 'r' not as the only failsafe, but check it too with a simple print, if you have to troubleshoot.
And I agree with Caleb below -- why do this and risk file-locking or a mistake in the path, etc., not when you can read it directly. But I cannot assume to know why you are recording this to txt.
Using the ListTables() or Wayne's suggestion with the list "for table in ['Table_A','Table_B']:" would be much better. Also, one more tip is it is recommended to use the "os.path.join" (I have shortened it to p.join) to append path names rather than using the + and '\\' routine. If you could post what your text file looks like I can try to help you find the problem.
It could be confusing that the syntax of TableToTable has the 1st 3 params as TableName, destination workspace, TableName.
So, KPG, you could do this with the variables you established provided they are valid:
arcpy.env.workspace = source
arcpy.TableToTable_conversion(line, destination, line)
In fact you should probably make sure everything really exists before you get to the conversion line with something like:
import arcpy, os
from os import path as p
source= r'C:\Data\Data.gdb'
destination= r'C:\Data\Base.gdb'
Tables= r'C:\Data\Tables.txt'
w=open(Tables,'r')
lines=w.readlines()
for line in lines:
print (p.join(source,line))
arcpy.TableToTable_conversion(p.join(source,line),destination,line)
w.close()
and I still have the same error.
I attach jpg file to show the paths to my data and my txt file. I think that paths are correct.
Your solution are better than use txt file but I am new in Python and I try to understand why it does not work :).
I apologize for this madness :)
[ATTACH=CONFIG]20067[/ATTACH]
Attachments
Use the arcpy.Exists statement after you join the pathname to see if it 'makes sense' to arcpy.
Also, when you paste code, use the tags to preserve intention (use the # symbol or manually enter [/CODE] after the code and [CODE] before the code to set it apart). Maybe I missed it but did you attach any samples?
I would still recommend using the ListTables() function though. Here is a look at my results and text file:
[ATTACH=CONFIG]20068[/ATTACH]
Attachments
When I print your 'lines' variable (see below), I get the 'extra formatting' included - pretty certain you have to 'handle this' in your code because certainly arcpy doesn't know what the 'readlines' method is doing. Here's the trouble:
>>> print lines
['Table_A\n', 'Table_B']
What clued me in is that you said in your 1st message that you had no trouble when the file is populated with one table, so the crlf (carriage return linefeed) character is then included when you enter successive lines in the txt. Sorry for not seeing that earlier.
EDIT:
Right, so a simple solution is a 'slicing' trick [0:-1], to include with fetching the 'line':
(note: Make sure that for the last line in your file, you enter a line return before saving. Sometimes it's consider a better practice to include an END or endfile statement.)
Your error message stemmed from the line continuation character, this is true; however, it is important to investigate your error messages carefully, as the ERROR 999999 is a generic code. Exercise care with your variable references too, see (along with the attachment) the following interactive IDLE session (I apologize for the readibility; if you are having problems, it may be easier to read if you copy/paste into a text editor - I didn't intend for the text-wrapping as shown below):
Attachments
Note: When I neglected to strip the character from the 'source' param (the 1st param in TableToTable), it throws 'cannot find table'.
When I fixed that, but forgot to do it for the 3rd param, the table name, it found the table, just could not complete the execution.
EDIT: How many lines do you have in your text file?....and what do you get when you print tables.readlines()? I got (after opening the txt, pressing Enter (for a final return), and saving/closing file):
['Table_A\n', 'Table_B\n']
But I think you are onto something there - I didn't bother to include the file extension, not one for a file gdb... I was able to duplicate the 'The table was not found. [Table_A]' error with (which was successfully fixed via stripping the special character):
Ahh, I see. It does indeed give me a list with the new line '\n'. And that would explain why my initial results would print a new line before printing 'True'. However, it is strange to me that when I checked for the existence of the table, it returned true, apparently ignoring the '\n' at the end. I wonder why that is?
Here is what I get when I print the readlines(), so it appears you are correct.
['cama.dbf\n', 'cama_addresses.dbf\n', 'Duplicates.dbf']
Now I am curious as to why arcpy says these files exist. This is strange, but now more than ever I would like to emphasize to KPG that this whole process is unnecessary to begin with since the ListTables() would be a much better alternative. That way, you do not need to worry about strange things like that.
Regardless, in this case, you are right that it is irrelevant and a little bit foolish to want to do it this way rather than reading it directly UNLESS for some reason it is desired to 'create' the input params for TableToTable for bulk processing later without creating a 'staging' gdb. Maybe that was just the preference....at any rate, chalk it up to an 'academic' lesson. Trust me, this minute detail may be needed later. ...think KBG at least deserves a point for throwing us a curve ball! It has been handled, maybe not out of the park, but you know, on base somewhere....
['cama.dbf\n', 'cama_addresses.dbf\n', 'Duplicates.dbf']
Good to know! | https://community.esri.com/thread/65129-problem-with-import-table | CC-MAIN-2018-43 | refinedweb | 1,216 | 72.16 |
On Sat, Feb 21, 2009 at 04:32:47PM +0100, Stefano Sabatini wrote: >> She still can and should do #include <libavutil/avutil.h> > > and get done with the pix fmt stuff inclusion, so she may do: > #if (LIBAVUTIL_VERSION_MINOR < X) > #include <libavutil/avutil.h> > #else > #include <libavutil/pix_fmt.h> > #endif well ... > > Note that this currently doesn't make sense, since great one line summary ... ive not seen pix_fmt as a header the end user would want to include directly rather as "internal but installed" header to factorize our code. thus IMHO it wouldnt need a bump ... also fewer headers -> less compexity i know its trivial for us now but each additional (and useless so) header makes it more complex for the: <> | http://ffmpeg.org/pipermail/ffmpeg-devel/2009-February/065756.html | CC-MAIN-2016-44 | refinedweb | 120 | 74.29 |
I would like to have different applications under the same domain using Heroku.
Because of the name of the domain, I would like to access the applications using folders (mydomain.com/app) instead of using subdomains (app.mydomain.com), is this possible? Thanks
There is no type of URL re-writing you have access over thats going to do that for you. You could create a "stub" Siantra-based app that allows you to define those types of URLs, but it would have to effectively redirect you to the subdomain version.
I'd have to play devil's advocate and ask why you'd want to have things namespaced as /app instead of using subdomains. Subdomains offer much more flexibility and are a lot less brittle than essentially having to url-rewrite all the time based on the first "slash" element. | https://www.codesd.com/item/how-to-host-different-applications-without-subdomains-to-heroku.html | CC-MAIN-2021-17 | refinedweb | 141 | 63.29 |
im getting this error even though the findByPrimaryKey is defenitely there in weblogic.
[9.2.8] In EJB CspPasswordHome, the home interface must define the method.
I think source of error maybe that i can't add the custon primary key i wrote to the drop down list for the primary key type. How can i add it to the drop down list, or if i specify object than how else might this eror be occurring??
weblogic primary keys (1 messages)
- Posted by: iqbal ahmad
- Posted on: July 24 2000 18:43 EDT
Threaded Messages (1)
- weblogic primary keys by Amar Mehta on August 26 2000 22:42 EDT
weblogic primary keys[ Go to top ]
I'm kind of new to this too but I was able to create the .jar file with weblogic's ejbdeployer. I haven't tested it out yet though. Make sure your classes are similar to the following example.
- Posted by: Amar Mehta
- Posted on: August 26 2000 22:42 EDT
- in response to iqbal ahmad
When you're in ejbdeployer and you click on Persistence, the primary key type should be selected to AuthorPK in this case. Make sure primary key field is set to none. hope this helps.
//in the bean class
public AuthorPK ejbCreate(String id) throws EJBException, CreateException {
this.authorID = id;
return null; //return null for container managed EJBs
}
No finder methods -- they are implemented by the container.
//in the home interface
public Author findByPrimaryKey(AuthorPK key) throws FinderException, RemoteException;
//Primary key class
/**
* Primary Key class for 'Author' Container-Managed
* Entity Bean
*/
public class AuthorPK implements java.io.Serializable {
/**
* Note the primary key fields must be a
* subset of the container-managed Bean fields.
*/
public String authorID;
public AuthorPK(String authorID) {
this.authorID = authorID;
}
public AuthorPK() {
//empty! required by EJB 1.1
}
public String toString() {
return authorID;
}
public boolean equals(Object other) {
if(other instanceof AuthorPK) {
return authorID.equals( ((AuthorPK)other).authorID );
}
return false;
}
public int hashCode() {
return authorID.hashCode();
}
} | http://www.theserverside.com/discussions/thread.tss?thread_id=322 | CC-MAIN-2016-40 | refinedweb | 329 | 56.05 |
Hi all
I need to execute export of bibliographic records into Dublin Core format.
It seems to be a future planned aim:
is it possible to cooperate for the realization of the feature? Or simply to retrieve some informations about how to customize any personalized exports?
best regards
RM
Matthias Steffens
2011-12-12
Hi robmor,
refbase-0.9.5 does already support export of data in Simple Dublin Core XML format. In refbase, this format is also called "OAI_DC XML".
For an example output, see the "example" link behind "OAI_DC XML" on this page:
Alternatively, to perform a similar export via the refbase interface, you could also:
1. Log into as 'user-at-refbase-dot-net'.
2. Display the "Baltic Sea" group from the "Show My Group" form on the main page.
3. In the "Cite, Group & Export Options" (underneath the search results), export all found records as "OAI_DC XML".
HTH, Matthias
Matthias Steffens
2011-12-12
A few additions to my previous post:
If you're interested in export to Simple Dublin Core XML you may also want to have a look at the SRW_DC XML format whose record format is very similar to the OAI_DC XML format, but which adds tags of the PRISM namespace for better granularity.
Also, you can play with the different XML output formats (and have them displayed in your browser via a XSL stylesheet) using the refbase OpenSearch service:
More info at:
Matthias
Matthias Steffens
2011-12-13
Hi robmor,
what about other specifications as MARC, MARC21 and UNIMARC?
The MARC format (and all of its variants) is a very complex format that requires a lot of knowledge and experience (which I don't have). So, unless some third-party developer steps in, chances are not very high that support for these formats gets added to refbase any time soon. In the past, there hasn't been much demand from the refbase user base for these formats. And since refbase also supports MODS XML (v3.2), MARC data could be converted to MODS and then imported into refbase.
For mapping tables and conversion style sheets from MARC, MARCXML and Dublin Core to MODS XML, see:
If you tell us more about your anticipated workflow, we may be able to give you better advice.
Matthias
Hi Matthias
I'm still debating with my university about some export/import formats. Regarding OAI-PMH format (), I've seen that it should be covered. But when I try to execute the import using the previously generated oaidc_export.xml file my system generates following warning: Unrecognized data format! Moreover I've read in, it should be a future planned feature. Or?
Regards
RM
Matthias Steffens
2011-12-21
Hi robmor,
currently, refbase does not support the OAI-PMH protocol. Note that this is different from OAI_DC XML which is just a raw data format used for transport. I cannot tell you when refbase will support the OAI-PMH protocol, but it probably won't be soon. So, in your case, I would try to work with what is already avaailable.
This quote from my previous post is still relevant:
If you tell us more about your anticipated workflow, we may be able to give you better advice.
I.e., in other words:
- What is your use case for refbase?
- How is your refbase installation related to your university? I.e. what are the bigger goals?
- From what kind of system are you trying to import data into refbase?
- Which export formats does that system support?
In short, give us more details, and we may be able to serve you better.
Best, Matthias
Hi Matthias
- What is your use case for refbase?
To publish and mantain a specific bibliography for an exact study area: ladin pubblications. Data are actually stored into a temporary Oracle DB and I have to export them to a new Refbase system. (In progress)
- How is your refbase installation related to your university? I.e. what are the bigger goals?
To store data obviously, but mostly to offer a specific - user defined - citation layout (to be developed next year)
- From what kind of system are you trying to import data into refbase?
I wrote an external parser to convert data from a sort of 'flat' TXT file to XML, this in order to create a MODS XML file to import data into Refbase (now still not fully working)
- Which export formats does that system support?
all those already offered by Refbase are OK. In extension to this I have to provide an oai-pmh web service, not only a simple batch export (to be realized).
And/or a batch export to Marc21 (still to be defined)
regards
RM
Hi Matthias
up to what I understood till now, I have to setup an additional webserver like DSpace, oaicat, PKP Open Harvester Systems or others. After that I have to let the newly installed server to fetch data through a common metadata system, probably dublin core. The fact is that I have to write some functions to automate the export operations to dublin core. Or?
best regards.
RM
Richard Karnesky
2011-12-24
The tools that you list all do different things. DSpace is a full-blown institutional repository system (compare to eprints.org, Fedora, CDSware, and others). There is some overlap in what it offers and what refbase offers (though each product has some functionality that the other lacks). OHS is for harvesting and for handling the harvest. It is more of a client application compared to the servers you list. OAICat is more similar to what you describe.
I'd imagine that what would be more useful & a similar amount of work would be to add OAI-PMH functionality to refbase using a pre-existing PHP library, such as one of these (I haven't investigated them enough to plan the best way to go):
MODS->DC and MODS->MARC XML is trivial using XSLT. MARC XML->MARC21 is possible. The tools I link to can mostly draw from the database, itself & wouldn't require an exported intermediary.
-Rick | http://sourceforge.net/p/refbase/discussion/218757/thread/d9dcbd78 | CC-MAIN-2013-48 | refinedweb | 1,015 | 62.38 |
03-Nov-08 16:33:04,305 |ERROR|rs.remote.data.RemoteDataProvider|Timer-3 |Exception caught while subscribing to item 'floorupdate'...
Type: Posts; User: markgoldin
03-Nov-08 16:33:04,305 |ERROR|rs.remote.data.RemoteDataProvider|Timer-3 |Exception caught while subscribing to item 'floorupdate'...
I got new license and it's working, thanks.
No, sorry, I dont, but I can provide any detail you would need.
I have downloaded new LS version.
I have followed intsructions to configure a free version: lincense file and conf file with both lincense and userId. But I am getting:
icense not valid (7)....
Here is my startup page:
<html>
<head>
<HTA:APPLICATION ID="oHTA"
APPLICATIONNAME="myApp"
BORDER="solid"
BORDERSTYLE="none"
CAPTION="yes"
MAXIMIZEBUTTON="yes"
When I start my push page in IE8 I see a small "ghost" page in the middle of the screen. Nothing like this in IE7. Any idea what that is?
Thanks
Just wanna tell you that you were right, it was my mistake: My testing data generator is not in fact sending data every second. Unless something else, my solution is ready to go. Thank you so much...
Yes, I did comment out the update call. I still had lost data, I would say less then with updates but still there was lost data. Knowing my code would you recommend anything to preotect from losing...
I am going to follow your recomdations but I think the reason for missing data is that sometimes data push by the LS takes just a moment longer (means resources are still busy) and my data adapter...
Here is my latest code with which I am missing some data sometimes:
using System.Collections;
using System.Threading;
using System;
using System.Runtime.InteropServices;
using...
Here is my latest code. I understand that you are not supporting .Net but still maybe you can give me a hint:
using System.Collections;
using System.Threading;
using System;
using...
Yes, I did that, compiler did not ask for other functions. But I haven't tested sending message yet.
This is the code from HelloWorld .Net adapter sample:
public void Run()
{
go = true;...
Ok, while I was creating MessageAwareLiteralBasedProvider class:
using System;
using System.Collections;
using System.Threading;
using System.Net;
using System.Net.Sockets;
using System.Text;
...
Ok, the exact message is:
<INFO> Refused Request: Session error: Unsupported function from ipxxxx : xxxxport
This is my function from the push page:
function sendMessage(message)
{
...
How do I override notifyUserMessage to have my code there?
Also here is a fragment of my push page:
ls = "";
page.onEngineCreation = function(lsEngine) {...
But isn't sendMessage a server side method?
How am I triggering it from the client (Browser)?
Thanks
Does that require Java backend?
I am running .Net data Adapter though. Will it work then? If yes, could you please show some sample code?
Thanks
It could have been explained before but I have to ask this again:
Is it possbile to send some data back to the server (data adapter) from the client page?
If yes, any samples available?
Thanks...
So, current version of LS will be able to work with multiple adapters as long as these adapters serve different client pages?
If I can run more then one .Net adapter with LS Server how do I configure a single LS instance to work with multiple adapters? If that scenario works do I need to have an executable per each .Net...
While I am working on that I have another question:
Is it possible to hide these DIVs so they will not take any space on a page:
<div source="lightstreamer" table="hellotable" item="greetings"...
Alright, I uderstand.
I want to show a code fragment from my modified Hello World:
<script>
/////////////////PushPage Configuration
var debugAlerts = true;
var remoteAlerts = false;
... | https://forums.lightstreamer.com/search.php?s=52b9b19e023efde23ef2bee4c1ef6304&searchid=786142 | CC-MAIN-2019-51 | refinedweb | 628 | 69.28 |
Death by pointers
Introduction
In this post we will discuss a few widespread types of vulnerabilities related to the insecure use of pointers and how these can be fixed. To be more precise, we will cover buffer overflow and format string vulnerabilities.
Buffer overflows
Generally speaking there are two types of overflows: out-of-bounds read and out-of-bounds write. We shall begin with the more widely known out-of-bounds write.
Out-of-bounds write
An out-of-bounds write occurs when number of copied bytes exceeds the destination buffer size. In consequence, the memory area adjacent to the buffer is overwritten. Depending on the buffer location, overflow depth and control over the copied data, the results range from an uncontrolled program crash to runtime-control of the program.
#include <string.h> void shell() { system("/bin/sh"); } int main(int argc, char** argv) { char dst[100]; memcpy(dst, argv[1], strlen(argv[1])); }
Exploitation
Let us begin by compiling the code. For the sake of simplicity, we will compile it without a stack canary and without the position-independent code option. This will allow us overflowing the buffer without triggering any alarms as well as, due to lack of address randomization on the code segment, to redirect the program flow to a fixed location.
gcc -m32 -fno-stack-protector test.c -o test
In the next step we will exploit the vulnerability. To do so, we first determine the address where you intend to divert the program flow. In our case, this is the address of the
shell() function.
nm ./test [...] 0804847d T shell [...]
Finally, we craft a payload that will overwrite the return address stored on the stack with the address of the
shell() function and pass it as an argument to the program.
./test $(python -c 'import struct; print "A"*112 + struct.pack("<I", 0x804847d)')
Out-of-bounds read
An out-of-bounds read occurs when the number of copied bytes exceeds the source buffer size. Depending on the buffer location and overflow depth, the results range from an uncontrolled program crash to information leakage. An example of this can be seen below.
#include <string.h> #include <stdio.h> int main(int argc, char** argv) { char key[10] = { 0x73, 0x65, 0x63, 0x72, 0x65, 0x74, 0x6b, 0x65, 0x79, 0x00 }; char src[10] = { [0 ... 9] = 0x41 }; char dst[20]; memcpy(dst, src, sizeof(dst)); printf("%s", dst); }
Exploitation
Once again, if you're interested in seeing the impact of the vulnerability for yourself, just compile and run the program:
gcc -m32 -fno-stack-protector test.c -o test
./test AAAAAAAAAAsecretkey
The fix
There are several ways how buffer overflow vulnerabilities can be addressed. One way is to perform bounds checking yourself. To simplify the process and prevent human errors, we recommend implementing an easy-to-use macro that will do most of the heavy lifting:
#define SAFE_MEMCPY(dst, src, dstSize, srcSize, copySize) \ { \ if( !ISNEG(copySize) && !ISNEG(srcSize) && !ISNEG(dstSize) && \ !ISNULL(src) && !ISNULL(dst) && \ !ISOVERFLOW(copySize, dstSize) && !ISOVERFLOW(copySize, srcSize) ) \ memcpy(dst, src, copySize); \ } #define ISNEG(X) (!((X) > 0) && ((X) != 0)) #define ISNULL(X) ((X) == NULL) #define ISOVERFLOW(X, Y) ((X) > (Y))
Format string vulnerabilities
A format string vulnerability occurs when an attacker obtains control of format string parameters. Depending on the degree of control over the format string and other factors, the results can range from an uncontrolled crash to runtime-control of the program. Note that format string vulnerabilities are particularly severe, since they can be used to perform arbitrary read/write operations.
#include <stdio.h> #include <string.h> #include <stdlib.h> void shell() { system("/bin/sh"); } int main(int argc, char** argv) { char buf[100]; if(argc != 2) exit(EXIT_FAILURE); memcpy(buf, argv[1], sizeof(buf)); printf(buf); printf("Done!\n"); }
Exploitation
Just as before, let us begin by first compiling the code with the default options. These include only one security-relevant option, the stack canary.
gcc -m32 test.c -o test
Each ELF binary contains a section referred to as the Global Offset Table (GOT). Essentially, it stores a set of addresses to external functions, such as the
printf() function contained in the standard
libc library. By default, unless signalled otherwise during compilation, these addresses are resolved at runtime by the dynamic linker. Since the dynamic linker is allowed to overwrite these values at runtime, so are we. To do so, we first find the location of the
printf() function in the GOT table.
readelf -a test | grep printf
0804a00c 00000107 R386JUMP_SLOT 00000000 printf
Next, we determine the address of the code where we intend to divert the program flow. In our case, this is the address of the
shell() function.
nm test | grep shell
080484cd T shell
Finally, we overwrite the address of the
printf() function in the GOT table with the address of the
shell() function. This will effecitvely cause the program to jump to it once it is called.
./test $(python -c 'import struct; print struct.pack("<I", 0x804a00c) + struct.pack("<I", 0x804a00d) + struct.pack("<I", 0x804a00e) + struct.pack("<I", 0x804a00f) + "%189x" + "%6$n" + "%183x" + "%7$n" + "%128x" + "%8$n" + "%4x" + "%9$n"')
The fix
Since the root of the problem lies in a user-controlled format string, the solution is simple. Do not use user-controlled input for the format string parameter in
printf() and other functions from the same family. Hence, for the example above, the fix would look as follows.
#include <stdio.h> #include <string.h> #include <stdlib.h> void shell() { system("/bin/sh"); } int main(int argc, char** argv) { char buf[100]; if(argc != 2) exit(EXIT_FAILURE); memcpy(buf, argv[1], sizeof(buf)); printf("Buf: %.*s\n", sizeof(buf), buf); printf("Done!\n"); } | http://enetium.com/death-by-pointer/ | CC-MAIN-2017-30 | refinedweb | 946 | 57.27 |
#include <qgsattributedialog.h>
Create an attribute dialog for a given layer and feature.
Create an attribute dialog for a given layer and feature.
Returns reference to self.
Only here for legacy compliance
Is this dialog editable?
Restores the size and position from the last time this dialog box was used.
Saves the size and position for the next time this dialog box will be used.
Sets the edit command message (Undo) that will be used when the dialog is accepted.
setHighlight
Toggles the form mode between edit feature and add feature.
If set to true, the dialog will be editable even with an invalid feature. If set to true, the dialog will add a new feature when the form is accepted.
Show the dialog non-blocking.
Reparents this dialog to be a child of the dialog form and is deleted when closed. | http://qgis.org/api/classQgsAttributeDialog.html | CC-MAIN-2014-42 | refinedweb | 142 | 68.06 |
CSS methodology: To BEM or not?
Is writing CSS the BEM way a good idea? I've been struggling to figure out whether I should start writing CSS that way because I just haven't been able to get over the fact that BEM naming tends to be long and it is tedious to have to give every single element a class name. I do see its modularity, but I've always thought that I could get that by giving each section a unique class name and write nested CSS from there just like how they write HTML in CSS Zen Garden site. Am I missing something here?
If you don't know what BEM is, take a look at getbem.com for a detailed guideline and sample code. I am not convinced of their claims.
They say I should care because BEM supposedly fixes the two most significant common issues:
1) CSS Inheritance
Their argument seems to be that CSS inheritance is infinite without scope or closure, and BEM can provide some scope by using unique CSS classes per element.
2) CSS Specificity
They argue that developers often find themselves using very long nested CSS selectors or the '!important' keyword to overcome existing specificity in an existing project someone else created. It results in a complicated mess of overlapping and conflicting CSS rules. BEM supposedly tames such situation by keeping CSS specificity to a minimum. They also say that BEM makes CSS code readily portable to a different HTML structure. They further argue that BEM avoids CSS conflicts by using unique contextual class names for every block, element and modifier combination and makes it much easier to maintain the codebase.
I'm not entirely convinced. Doesn't wrapping a module with a class/ID and avoiding abusing IDs and !important in the first place solve these problems?
They say that BEM helps to have fewer things for a browser to evaluate, which supposedly results in rendering a webpage faster. Supposedly, locating a class name is faster than evaluating nested CSS definitions. But, by how much?
Write your answer…
BEM is the type of nonsense the OOCSS fanboys cream their panties over, and to me it only contributes to bad practices of not leveraging selectors properly. Classes and ID's should be a last resort AFTER you've used up your semantic tags, not your go-to to slop onto everything.
You can TELL the folks who encourage the use of BEM are -- as I oft point out -- unqualified to write HTML or CSS; as evidenced by such gems of ignorance and ineptitude (there are those two words again) as:
<div class="block block--size-big block--shadow-yes">
Classes saying what things look like and not what they ARE? Classes that are redundant to inheriting off the parent? That's both pointless code bloat AND presentational use of classes, a double /FAIL/ at web development.
Hardly a shock that 'getbem" website is itself a bloated wreck using two to three times the HTML necessary to do the flipping job!
Overall it reeks as the same garbage some folks advocate of slopping classes onto everything to avoid using selectors entirely -- one of the DUMBEST pieces of advice and based entirely on a LIE about how selectors slow down the render time.
If your site is well coded, render time should be bupkis, at least compared to handshaking and transfer time. Slopping out two dozen separate stylesheets and two to ten times the markup is going to effect your page loading time a hell of a lot more than "oh noes, you used child selectors four deep!".
Much like the idiocy that are front-end frameworks, OOCSS, SCSS, and all the other hot and trendy media darlings, their claims are 100% bunko, the people creating them seem to have failed to grasp the most basic concepts of HTML and CSS, and in general they're a blight upon web development as a whole. AT BEST they are crutches for the inept, at worst... I lack the words in polite company.
That and to be frank, I do not find it aids in clarity or legibility one iota -- quite the opposite in personally think BEM is overkill, and leads to bloated HTML and CSS. I think the way class names are used doesn't make the best use of CSS features (which can match parts of attribute values, if a value starts with, contains anywhere, contains in a space-separated list, or ends with a value).
Also keep in mind that BEM came around in 2013 (half a decade ago) mostly to deal with the way HTML was written for pre-flexbox, pre-grid layouts. There are better, stronger, more lightweight ways we can build HTML now, which means to a great extent, the problem BEM aims to solve doesn't need to exist as much anymore.
But, I won't say not to use it, or that it's bad. It works, so just take the parts of it that still make sense to the technology, and use the parts that actually give you a boost when you're naming things or writing stylesheets. There's no need to adhere to it strictly or fully, just use it so far as it helps you and no further :D
I've actively used BEM for a few years now, and it helped me a lot. I think, BEM is a great tool to write lean CSS. However, it might as well be one of the hardest to learn and use correctly. That's why some people are against its usage and others shy away from it. To be honest, I still wouldn't say that I am very good at writing BEM myself One might say that that's one of its flaws: it's hard to name a block and not fall back to creating scopes inside the name.
However, the basic usage of BEM yields great benefits. By looking at a class name, you instantly can deduce, which elements should be affected and where they are probably located, if you know the general site layout - even after years, or on a foreign codebase. You do not need long names to achieve that, either. All you have to do is sit back a bit, move your mind a step away, and think about where the element is located logically (not in your HTML structure, which is what you are probably thinking about at that moment).
Another positive aspect of BEM is that it yields a flat hierarchy. There is not sub-element selector. You can easily leverage and mix it with many other CSS tools. For example you can re-order your classes in an inverse specificity (ITCSS: Inverse Triangle CSS), which means that more specific selectors automatically overwrite inheritance from higher selectors in your HTML structure, which leads to you not having to worry about what will change on the rest of the page (by CSS inheritance), and how to make a style even more important after you already used
!important.
Of course, BEM can be mixed with SCSS. You can use SCSS to split up your huge file, you can define your basic design colors, you can create mixins for your transitions and a lot more. Just don't do scoping.
BEM can also be extended by applying namespacing, which adds additional information, for example if the class only affects a single element, or might affect 0..n elements, or should not be touched by anyone, even though it has no selector in CSS, because it is used in a script. Namespacing makes it easy to deduce how changes to a class might affect the whole page.
I highly recommend reading about BEMIT and ITCSS. That's where I learned from, and that's what I made very positive experiences with. The one behind these articles and methods, Harry Roberts, also hosted an AMA here on Hashnode some time ago, you should check it out, too ;)
I thought about using BEM and tried to use it, but I have quietly gone away from it again. As you point out the naming conventions are often very and it leads to a few overhead problems:
- Hard to remember the correct path name and no IDEs will help you
- If the structure changes you might have to refactor a lot of CSS
- Longer class names means more bytes, not much, but it's a margin
Since I'm uing
SCSS it makes more sense to try to adapt a namespace OOP pattern to my CSS. Simply if I have a component
testimonials that would be:
.testimonials { > .testimonial { > .title { // CSS } } }
If you are consistent doing this and not making an independent
.title then this approach works very well in my opinion.
If you want to have a generic class, you can always use BEM here:
.utilitiy__ { &title { // CSS } }
But you could also simply call it
.title as it would still not be inherited from a
.testimonial
BEM is a waste of time, imo. It takes longer to learn what NOT to do when you "BEM the rules" than it would just to do it in a dev-friendly, DRY manner. It seems to encourage folks to ignore the "Cascading" in CSS way too often - which is like trying to use nothing but an open flame, and your hands, to cook an egg.
Also, if you're having a hard time evaluating any type of code, you may need to blame the person who wrote it.
The Dev Community
(Free, friendly and inclusive)
A network for software developers to learn new things and get insight into the world of programming | https://hashnode.com/post/css-methodology-to-bem-or-not-cjmwskdv901sbbts2pkanc3gr | CC-MAIN-2018-43 | refinedweb | 1,616 | 66.57 |
Worksheet append not populating row_dimensions properly
As the title says, using ws.append does not properly populate row dimensions.
To reproduce, you can use the following code:
from openpyxl import Workbook wb = Workbook() ws = wb.active ws.append(['a', 'b', 'c']) ws['A2'] = 4 ws['B2'] = 3 print vars(ws.row_dimensions[1]) print vars(ws.row_dimensions[2])
Output is:
{'index': 1, 'worksheet': None, 'collapsed': False, 'ht': None, 'outlineLevel': 0, 'hidden': False} {'index': 2, 'worksheet': <Worksheet "Sheet">, 'collapsed': False, 'ht': None, 'outlineLevel': 0, 'hidden': False}
This breaks styling rows using the documented way of adding styles to rows, since the worksheet is None, resulting in an AttributeError.
Setting cells manually properly populates the worksheet variable, which is expected behavior.
Using the latest version of openpyxl from pip (2.1.2)
Make worksheet a compulsory argument for dimensions. Resolves
#379
→ <<cset 15df5c893a14>>
Thanks for this. I think I've just fixed it. @Eric Gazoni can you have a look at the change to see if it will affect your stuff?
Removing version: 2.1.x (automated comment) | https://bitbucket.org/openpyxl/openpyxl/issues/379 | CC-MAIN-2018-30 | refinedweb | 175 | 51.55 |
by Tom Ortega II
Many of you already use Adobe Flex to build rich Internet applications. For the uninitiated, you may be wondering what makes building Flex applications so easy. It's no mystery. For starters, the Flex framework is essentially a library of prebuilt components — including containers, buttons, combo boxes, and text fields. With Flex Builder, you can build your application by simply dragging and dropping these components into your application.
But while your choice of components is vast, eventually you'll find yourself with a need that hasn't been fulfilled. What then? Since Flex is open source, you can view the source code to see how the components are constructed and then modify or build new components to suit your need.
In this article, I show you three ways to create custom components for your Flex applications. Each one is a bit more complicated than the last. However, the nice thing with Flex is that you can create components that are as simple or as complex as you like. Just find a method that works for you and use it until it just doesn't work anymore, and then increase the complexity. The three styles I cover are as follows:
You'll notice that I put the particular coding style in parentheses. One thing to remember is that these are the coding styles that the components are created in. However, this does not mean that you can only use them in the same style. As you'll see, you can use the components in your applications either as MXML tags or ActionScript classes, regardless of how they were coded because all MXML files get converted to ActionScript files by the Flex compiler. MXML just makes the user's life easier.
Before you begin creating custom components, you need a Flex project to house them in. A Flex project is a way to tell Flex Builder that a certain set of component classes (that is, files) are tied to a particular application:
You now have a new project entitled EdgeArticle with a single file named Main.mxml in the src folder. The Main.mxml file should be open on the screen with nothing more than an opening and closing
mx:Application tag. The "mx:" is just a namespace for built-in Flex Framework classes. Later, Flex Builder will create a
local: namespace for you to use. Moving forward though, I will drop the namespaces when referring to a component; therefore, the
mx:Application tag will be referred to as just the
Application tag.
Before moving on, you need to change one value. In the opening
Application tag, set the layout attribute to vertical instead of the default, which is absolute. There are many reasons for this change, but for your purposes, this will cause your application to center your components and line them up vertically with some layout padding.
Now it's time to create your first custom component, which is a compound type built in MXML. You will then nest other MXML tags inside of the root tag to create the component. These MXML tags are predefined components that you combine to make a new component.
Choose File > New > MXML Component. Make sure all the values match those in Figure 1.
Figure 1. Creating an MXML component.
Now, you need to add some code to create the login screen. In the LoginScreen.mxml file, add the following code between the
TitleWindow tags:
<mx:Form> <mx:FormItem <mx:TextInput/> </mx:FormItem> <mx:FormItem <mx:TextInput/> </mx:FormItem> </mx:Form> <mx:HBox> <mx:Button <mx:Button </mx:HBox>
This code can be added manually in Code view or by dragging and dropping in Design view. Regardless of which method you use, your code should look like Figure 2.
Figure 2. The LoginScreen.mxml file.
Now you have a form with two FormItems: one is a TextInput for username, and the other is a TextInput for password. In addition, you have an HBox with three buttons. The HBox is just a way to easily lay out items horizontally. Note that the buttons are not inside the form. Unlike HTML, the
Form tag in Flex is just a layout mechanism instead of some sort of logical container.
To view the new compound component, you need to add it to your Main.mxml file. Place your cursor on line 3 in Main.mxml, which is the blank line between the two
Application tags. A nice feature of Flex Builder is auto complete. If you type <Login, your screen should look like Figure 3.
Figure 3. The Flex Builder auto-complete feature.
Choose the value
local:LoginScreen. Flex Builder then automatically adds a new namespace for local in your opening
Application tag. Namespaces are simply a way for people to use the same name, such as LoginScreen, without stepping on each other's toes. Flex uses that namespace to determine which version of a component to use. Your final Main.mxml should look like Figure 4. Note the new
LoginScreen tag and the local namespace in the
Application tag.
Figure 4. The Main.mxml file.
Now that your application is ready to go, it's time to see the working application. To do this, you need to run the application. Choose Run > Run Main.
Flex Builder now takes your code and compiles it into a SWF file that runs in a browser. Once it's finished compiling, it opens up the file in your default browser. Your finished application should look like Figure 5.
Figure 5. The new LoginScreen compound component running inside the application.
Now you have created your first compound component in Flex.
In object-oriented programming (OOP), you have a base object. New objects then inherent from the base object or extend it. For example, let's say that Shape is your base object. You could have two shapes, Polygon and Ellipse, which extend your base Shape. Circle could then extend Ellipse. The concept here is that you start broad and specialize as you extend further and further down.
In Flex, the objects you use most are classes. The Object class is the base class of the ActionScript 3.0 OOP model. You create classes by creating MXML or ActionScript files. In the LoginScreen.mxml example, you created an MXML class, which extended the TitleWindow class.
What I refer to as a template component is one that you extend with a purpose. Let's look back at the LoginScreen. It has two buttons, but they're not the same size. You could manually size them by setting the width on each button. However, to make all the buttons in your application the same size, you need to extend the Button class to create your own SizedButton so all the buttons share the same height and size.
Choose New > ActionScript Class. Make sure all values match those in Figure 6.
Figure 6. Creating an ActionScript component.
The code that you're going to add is pretty trivial. In the class constructor, add a few lines of code. The constructor is the function that has the same name as the class. Each time you create a new instance (that is, a copy) of the class, it will be called. Therefore, any code you add here will also be called for every new instance. In line 9 where it says
super();, add the following code:
this.width = 180; this.height = 30; this.setStyle("fillColors",[0xFFFFFF,0xFFEFDF]);
This code is fairly self-explanatory. The word
this is a way of designating that you're referring to the properties of the class (meaning
SizedButton). You can see that the default width is set to 180 pixels, the default height is set to 30 pixels, and a new default gradient is set for the button fill colors. Your code should look like Figure 7.
Figure 7. The SizedButton.as file.
To see the fruits of your labor, you need to use the new component in your application. Therefore, go back to the LoginScreen.mxml file. In this file, swap out the
mx:Button tags for
local:SizedButton tags. While you're there, go ahead and give your TitleWindow a label as well. To do that, just add a title attribute to the
TitleWindow tag. This is the same as setting the width and height properties above, but it's in MXML instead of ActionScript.
Your modified LoginScreen.mxml should look Figure 8. Note the changes on lines 2, 12, and 13.
Figure 8. The LoginScreen.mxml file with the SizedButton tag.
Now when you run your application, you'll see that your buttons are the same size no matter what the label is, plus they have a new color scheme. Your TitleWindow is also now living up to its namesake by displaying the title value. Note the new look of the buttons and the new title of the window.
Homegrown components refer to components that you build that aren't really based on anything. These are components you create from scratch for a very specific purpose. To create this kind of component, you extend the UIComponent class, which is the class that most of the Flex visual components extend.
To fully understand what goes into creating these advanced components, I highly recommend you learn more about the Flex component lifecycle. The Advanced Visual Components in ActionScript Guide is a great resource to learn all the many facets of this process. For the advanced component, I'll show you how to use two of the methods of the lifecycle: createChildren and updateDisplayList.
To get started, create a new ActionScript class by choosing New > ActionScript Class. Match the values in Figure 9.
Figure 9. The FadingRectangle ActionScript class.
This time, you will extend UIComponent. You want the FadingRectangle component to create a rectangle that has a gradient fill. When users move their mouse across this component, its alpha transparency values will change randomly based on the mouse location. It's not a very practical component, which is why it is not part of the Flex framework. However, this just demonstrates the power of Flex and how it can not only accommodate obvious business needs, but also give you the raw power to handle almost anything.
Here is the code for the class:
package { import flash.display.GradientType; import flash.events.MouseEvent; import mx.core.UIComponent; public class FadingRectangle extends UIComponent { public var value:Number = 9; public var sprite:UIComponent; public function FadingRectangle() { super(); } override protected function createChildren():void { super.createChildren(); sprite = new UIComponent(); addChild(sprite); sprite.addEventListener(MouseEvent.MOUSE_MOVE,changeValue); } override protected function updateDisplayList(unscaledWidth:Number, unscaledHeight:Number):void { super.updateDisplayList(unscaledWidth,unscaledHeight); sprite.graphics.clear(); sprite.graphics.beginGradientFill( GradientType.LINEAR, [0x0067AC, 0x002E56], [value % 10 * 0.1, value % 10 * 0.1], [0,255],horizontalGradientMatrix(0,0,300,50)); sprite.graphics.drawRoundRect(0,0,300,50,3); sprite.graphics.endFill(); } public function changeValue(event:MouseEvent):void { value = event.localX + event.localY; invalidateDisplayList(); } } }
You should be able to copy and paste this code to completely overwrite the file contents of the FadingRectangle.as class.
Let's take a closer look at the code. First, we created two properties (also called class variables):
public var value:Number = 9; public var sprite:UIComponent;
The
value property is used to calculate the alpha level of the rectangle. The
sprite property is a UIComponent where we draw the rectangle.
Next, we override the
createChildren function so we can add our own children to the component. The child we want to add is the sprite where we will be doing all of our drawing:
override protected function createChildren():void
Additionally, we set up an event listener on the sprite. Specifically, we say that if the mouse rolls over the rectangle, call the
changeValue function:
public function changeValue(event:MouseEvent):void
Inside this function, we set the value for later use. We then call
invalidateDisplayList(). This just tells the Flex framework that we need to redraw the component again:
override protected function updateDisplayList(unscaledWidth:Number, unscaledHeight:Number):void
We override this function so we can draw (and redraw) our rectangle. Each time, we adjust the alpha levels based on the last mouse location.
The last thing you need to do is add it to your LoginScreen component. Add it under the buttons so that your LoginScreen code now looks like Figure 10. You can see your new component on line 15.
Figure 10. The LoginScreen component with the fading rectangle.
Run the application again. Move your mouse around under the buttons. You should see the rectangle fading in and out based on your mouse movement. If you haven't been building all along but you want to see the finished application, check out Figure 11 (it's interactive).
To view this content, JavaScript must be enabled, and you need the latest version of Adobe® Flash® Player.
Download the free Flash Player now!
Figure 11. The completed application with all three custom components.
As you can see, building custom components inside Flex can be accomplished in more than one way. You can create a new component by putting lots of other components together. You can create customized versions of existing components by merely extending them with some default properties. You can even break away from the normal class types but still leverage and harness the full potential of the Flex Framework.
The attraction of Flex lies in its underlying component makeup. The ability for developers to compose, extend, or create components is powerful. It enables quick yet robust development of today's demanding rich Internet applications. If you need a component, chances are someone has already built it. If not, you can share yours once you create it.
If you want to learn more about custom components, there are plenty of resources. Flex.org and the Flex Developer Center are great places to start. Adobe's online resources for Flex 3 are also helpful. Lastly, if you want to experience the Flex community, attend the next 360|Flex conference or find your local user group.
Participate in a survey about developer tools and services… and be entered to win a 32 GB Apple® iPod Touch". | http://www.adobe.com/inspire-archive/august2008/articles/article5/index.html?trackingid=DLFXK | CC-MAIN-2014-35 | refinedweb | 2,358 | 66.33 |
KinoSearch::Document::HitDoc - A document read from an index.
The KinoSearch code base has been assimilated by the Apache Lucy project. The "KinoSearch" namespace has been deprecated, but development continues under our new name at our new home:
while ( my $hit_doc = $hits->next ) { print "$hit_doc->{title}\n"; print $hit_doc->get_score . "\n"; ... }
HitDoc is the search-time relative of the index-time class Doc; it is augmented by a numeric score attribute that Doc doesn't have.
Set score attribute.
Get score attribute.
KinoSearch::Document::HitDoc isa KinoSearch::Document::Doc isa KinoSearch::Object::Obj.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. | http://search.cpan.org/~creamyg/KinoSearch/lib/KinoSearch/Document/HitDoc.pod | CC-MAIN-2018-13 | refinedweb | 113 | 50.73 |
Compilation errors in Arduino 1.6.5
I have just found issues with Arduino environment.
Adding the following
#include <SD.h>
#include <FS.h>
#include <FSImpl.h>
#include <vfs_api.h>
#include <M5Stack.h>
#include <SPI.h>
#include <Wire.h>
#include <M5Stack.h>
Is needed to get the examples to compile.
Are you actually using Arduino IDE version 1.6.5 from 2015 - or is that a typo ?
From your comments, I am not sure what issue you have found.
Depending what sketch you are trying to load will dictate what libraries will need to be referenced at the start of the sketch, such as those you list.
If you are having problems loading the examples, perhaps pick one and outline some specific details including error messages. | http://forum.m5stack.com/topic/237/compilation-errors-in-arduino-1-6-5/2 | CC-MAIN-2018-34 | refinedweb | 126 | 72.73 |
In the button handlers for your buttons you need the following code:
foreach (var item in dataSource)
{
item.Checked = true; // or false for ClearAll
}
You change the values in the source data and the UI will update to reflect
that change.
The simpliest way is to use ko.mapping.fromJS
Take a look at this fiddle
var addonsData = [{
sku: 201,
name: "addon A",
price: 1
}, {
sku: 201,
name: "addon B",
price: 2
}, {
sku: 201,
name: "addon C",
price: 10
}];
function viewModel(ad) {
var self = this;
var mapping = {
create: function (item) {
item.data.selected = ko.observable();
return item.data;
}
};
this.addons = ko.mapping.fromJS(ad, mapping);
this.selectedItems = ko.computed(function () {
return ko.utils.arrayFilter(self.addons(), function (item) {
return item.selected();
});
});
this.total = ko.computed(function () {
return self.selectedItems().length;
});
this.totalPrice =
For requirement #1, the checkchange listener is indeed the right place to
implement it.
To get all the records in the group, you need to grab a reference to the
grid's store, and then use its query method, with your grouping field, and
the value in the checked record.
Here's an example:
checkchange: function(col, index, checked) {
var grid = col.up('tablepanel'),
store = grid.getStore(),
record = store.getAt(index),
group = record.get('group'),
// returns a MixedCollection (not a simple array)
groupRecords = store.query('group', group);
// apply the same check status to all the group
groupRecords.each(function(record) {
record.set('checked', checked);
});
}
For your second requirement, I don't really understand when you
Give the price inputs a class of "price" or something similar, and give the
name inputs a class of "name" or somthing similar.
Then bind the events using the class selector, and find the corresponding
checkbox using next('.price') or previous('.name')
You would need to iterate over the cheboxes. And change event makes more
sense when you are talking in terms of checkboxes..
Use on to attach events instead of bind
$(document).ready(function () {
// cache the inputs and bind the events
var $inputs = $('input[type="checkbox"]')
$inputs.on('change', function () {
var sum = 0;
$inputs.each(function() {
// iterate and add it to sum only if checked
if(this.checked)
sum += parseInt(this.value);
});
$("#price").val(sum);
});
});
Check Fiddle
function getCheckedBoxes(chkboxName) {
var checkboxes = document.getElementsByName(chkboxName);
var checkboxesChecked = [];
// loop over them all
for (var i=0; i<checkboxes.length; i++) {
// And stick the checked ones onto an array...
if (checkboxes[i].checked) {
checkboxesChecked.push(checkboxes[i]);
}
}
// Return the array if it is non-empty, or null
return checkboxesChecked.length > 0 ? checkboxesChecked : null;
}
// Call as
var checkedBoxes = getCheckedBoxes("mycheckboxes");
Live DEMO
Also try this one
$("#clickme").click(function(e){
var selected = $("#checkboxes input:checked").map(function(i,el){return
el.name;}).get();
alert("selected = [" + selected + "]
as string = "" + selected.join(";") + """);
});
The problem with having the code in "Calculate", is that you can't
determine whether the user clicked on a checkbox or edited the cell
contents.
To get rid of this proble, I would suggest that you have distinct code for
each of the events:
If user clicks on a checkbox, you can use the Checkbox##_Click event, and
place the checking code there. (Your CheckBoxes need to be ActiveX and not
Form controls)
If user changes the value in the worksheet, use the "Worksheet_Calculate"
to check the corresponding checkbox.
You can rely on the fact that Excel/VBA will always process the events in
the same order.
Now, one sad thing about CheckBoxes : You can access them throug the
OLEObjects collection of the Sheet (ActiveSheet.OLEOBjects("CheckBox1") but
you can't assign a value. So looping and us
How about:
Mousetrap.bind('right', function() {
if ($('li.active').is(':last-child'))
obj = $('li.active').parents('ul').next('ul').find('li').first();
else obj = $('li.active').next();
obj.click();
});
GlobalGraphOperations.at(graphDb).getAllNodesWithLabel(DynamicLabel.label('Label_Name'));
The way that we have found to do it is to find the property in object type
using Linq, and then using the GetProperty method to get the value:
bool isNullable =
(bool)column.GetProperty(column.ObjectType.Properties.Where(p => p.Name
== "Nullable").First());
This still doesn't feel like the best option, so if someone else has a
better answer please post it.
For dynamically created elements use jquery .live() method to bind events.
Jquery .on() or .click() [or any other event binders] will not work for
elements added dynamically. Just try it this way :
$(".delete").live('click', function(){
//Whatever you need to do...
});
Firstly the logic you have seems backwards to what you describe - you're
hiding the p element if there are multiple li elements found, not if there
are none. Secondly, closest() looks at parent elements, where as the p is a
sibling of the div, so you'd need to use prev() instead. Try this:
$('.clients').each(function() {
var $ul = $(this);
if (!$('li', $ul).length) {
$ul.closest('.clients_wrap').prev('p').hide();
}
});
Go to the DOM button in Firebug. In your search area type in 'document'.
Hit the '+' symbol and open it up. Click 'body', and so forth. Everything
starts at 'window'.
Hint:
Most of the time window is implicit, so you don't have to say
window.document.getElementById();, or even window.onload =
function(){*stuff here*/}. You do have to say window.onload if your testing
to see if it exists, though. document is a property of window and has a
series of its own properties and methods.
You might find this task much simpler if you were to use mmap(2). There
may be a C++ equivalent or wrapper, but I'm afraid I'm not much of an
expert on that front. Hopefully someone will come along with a better
answer if that's the case.
Here's a quick C (not ++) example. I'll see if I can google around and
C++ify it some more:
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
int main(void)
{
int fd = open("input", O_RDONLY);
struct stat s;
fstat(fd, &s);
// map the file as one big string
char *c = mmap(0, s.st_size, PROT_READ, MAP_SHARED, fd, 0);
// calculate sizes
int columns = strchr(c, '
') - c; // first newline delimits a row
int st
You should be more careful about the XPath syntax. The correct form of your
expression is
//item[@id='1']/ancestor-or-self::*/@label_position
You cannot use :: after a predicate, and you have to specify :: after an
axis.
What you really should be using is jQuery. Then you can just do this:
$("table")[0]
to select the first table of the document. Simple as that.
In other news, if that is your document, it isn't valid HTML, so Javascript
DOM isn't guaranteed to work.
If you are using C# you could do something like:
XDocument document = XDocument.Load("filePath");
var states = (from state in document.Root.Descendants("state")
where state.Attribute("id") != null &&
state.Attribute("id").Value == "1"
select state).ToList();
LIVE DEMO
$('.num').keydown(function (e) {
if (e.which == 34) {
$(this).closest('form').next('form').find('.num').focus();
return false;
}
if (e.which == 33) {
$(this).closest('form').prev('form').find('.num').focus();
return false;
}
});
As you can see I used .closest('form') it will allow you one day to use
your textarea inside a fieldset without taking care of the jQuery, cause
it'll always traverse the DOM the right way.
Another nice way: DEMO
$('.num').keydown(function (e) {
var k = e.which;
if ( k==34 || k==33 ){
$(this).closest('form')[k==34?'next':'prev']('form').find('.num').focus();
e.preventDefault();
}
});
Another nice DEMO
var $num = $('.num').keydown(function(e) {
var k=e.which, c=$nu
First you probably want to create a group inside a svg element. If you do
that, you can create the main group first, and for each element, create the
subgroups, binding the subProperties attribute to this subgroups:
var svg = d3.select('#chart').append('svg')
.attr('width', 100)
.attr('height', 100);
var data = [
{node : 1, subProperties : ["A", "B", "C"]},
{node : 2, subProperties : ["D", "E", "F"]}
];
var mainGroups = svg.selectAll('g.main')
.data(data)
.enter()
.append('g')
.classed('main', true);
mainGroups.selectAll('g.sub')
.data(function(d) { return d.subProperties; })
.enter()
.append('g')
.classed('sub', true);
I wrote a jsfiddle with the code here. Regards.
If this group of elements is always encapsulated within that .container div
element then this should work:
$(this).closest('div.conainer').find('.select')
This is using closest to traverse up the DOM hierarchy (parent elements)
and then find to traverse back down (child elements).
The delete_follower element is not a decedent of delete_followup element,
it is a sibling element so instead of find() you need to use siblings()
$(".delete_followup").click(function(){
var $this = $(this);
$this.siblings(".delete_follower").show();
});
If you absolutely have to do it, it would be more efficient to iterate
through the tree recursively, because then once you hit an element that is
less than what you need, you know nothing inside of it can be the required
size. Still seems like there would be a better solution under most
circumstances, but I don't know your specific problem.
EDIT:
This works.
function findElements( width, height, element ){
var results = Array();
for( var i=0; i<element.childNodes.length; i+=1 ){
var childElement = element.childNodes[i];
if( childElement.clientWidth == width &&
childElement.clientHeight == height ){
results.push(childElement);
results = results.concat(findElements(width, height,
childElement));
} else if( childElement.
what you want to do is traversing the tree with a depth-first algorithme.
You will find a lot of example over the internet. Depending on how you make
your tree. You can make a recursive algo passing each child from left to
right or using a visitor pattern if you got a tree of object already
loaded.
First, take a look at
if I think I understand the question correctly you are looking for a circle
around a given point on an image. I have posted some code below, that will
retrieve these points for you.
im = zeros([50,50]);
center = [20,20];
radius = 5;
x = 1:size(im,1);
y = 1:size(im,2);
[xx,yy] = meshgrid(x-center(1),y-center(2));
dist = sqrt(xx.^2+yy.^2)
circle = dist > radius-1 & dist < radius+1;
im would just be whatever the image is your are looking at
My suggestion is that you're using Checkboxes incorrectly. Checkboxes
should be used to select multiple elements. If you only want one element to
be selected then you should be using radio buttons which are explicitly
designed for this case. Then you won't need to use any JavaScript..
Python is close enough to pseudocode.
class counter(object):
def __init__(self, ival = 0):
self.count = ival
def count_up(self):
self.count += 1
return self.count
def old_walk_fun(ilist, func=None):
def old_walk_fun_helper(ilist, func=None, count=0):
tlist = []
if(isinstance(ilist, list) and ilist):
for q in ilist:
tlist += old_walk_fun_helper(q, func, count+1)
else:
tlist = func(ilist)
return [tlist] if(count != 0) else tlist
if(func != None and hasattr(func, '__call__')):
return old_walk_fun_helper(ilist, func)
else:
return []
def walk_fun(ilist, func=None):
def walk_fun_helper(ilist, func=None, count=0):
tlist = []
if(isinstance(ilis
"If a graph is disconnected, DFS won't visit all of its vertices. For
details, see finding connected components algorithm."
Reference: Algolist
You not are doing anything wrong. And your fix (finding other unvisited
nodes, and starting the algorithm again) is what other implementations do.
As further visible proof, look at this excellent implementation on TimL's
page. You can keep clicking and watch the DFS being executed. (Scroll down
to the middle of the page.)
You are returning tweets from repository, so each tweet in result should be
constructed. That's why parameterless constructor is required.
Constructing entities and mapping database fields to properties of created
objects is what ORM does for you. Btw, you can avoid entities construction,
if you will return only dates from database.
You just need to specify $myObject rather than myObject. This code snippet
produces the results I think you are looking for...
$obj = Get-Item C:Windows
$prop = "Name"
# prints Windows
Write-Host $obj.$prop
# prints 7
Write-Host $obj.$prop.Length
your code should be like this
$.each(vObj.tpaCo, function(key, value) {
console.log(key +':'+ value);
if(typeof(value)=='object'){
//console.log('Auditor length:'+vObj.tpaCo.value.length);
}
});
hope it helps..... | http://www.w3hello.com/questions/-How-can-I-traverse-through-all-of-the-checkboxes-in-my-ASP-NET-datagrid- | CC-MAIN-2018-17 | refinedweb | 2,050 | 60.31 |
mbstowcs — convert a multibyte string to a wide-character string
Synopsis
#include <stdlib.h> size_t mbstowcs(wchar_t *dest, const char *src, size_t n);
Description state. The conversion can stop for three reasons:
- An invalid multibyte sequence has been encountered. In this case, (size_t) -1 is returned.
- n non-L'\0' wide characters have been stored at dest. In this case, the number of wide characters written to dest is returned, but the shift state at this point is lost.
- The multibyte string has been completely converted, including the terminating null character ('\0'). In this case, the number of wide characters written to dest, excluding the terminating null wide character, is returned.
The programmer must ensure that there is room for at least n wide characters at dest.
If dest is NULL, n is ignored, and the conversion proceeds as above, except that the converted wide characters are not written out to memory, and that no length limit exists.
In order to avoid the case 2 above, the programmer should make sure n is greater than.
Attributes
For an explanation of the terms used in this section, see attributes(7).
Conforming to
POSIX.1-2001, POSIX.1-2008, C99.
Notes
The behavior of mbstowcs() depends on the LC_CTYPE category of the current locale.
The function mbsrtowcs(3) provides a better interface to the same functionality.
Example
mblen(3), mbsrtowcs(3), mbtowc(3), wcstombs(3), wctomb(3)
Colophon
This page is part of release 5.04 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at.
Referenced By
fstrcoll(3), fstrcolli(3), locale(7), MB_CUR_MAX(3), mbsrtowcs(3), mbtowc(3), wcstombs(3), wctomb(3), wprintf(3). | https://dashdash.io/3/mbstowcs | CC-MAIN-2020-45 | refinedweb | 290 | 65.93 |
Improved PHP solution stripping spaces and using a lambda for dryer code.
function stringsAreAnagrams($string1, $string2)
{
$stringToSortedArray = function ($string) {
$stringArray = str_split(str_replace(' ', '', $string));
sort($stringArray);
return $stringArray;
};
return $stringToSortedArray($string1) === $stringToSortedArray($string2);
}
Hi, here is my solution in JavaScript.
I’m sorry if my english is malformed somewhere, but it is not my native language.
This works by looping one time through both strings. Inside this loop I collect the number of occurrences of each character on each string. I collect these counts in two arrays, one for each string. In these arrays the indexes correspond to the char codes, and the values correspond to the counts.
After the loop I compare the two arrays and if they have the same count for the same characters, the strings are anagrams.
I’m assuming the strings will only contain uppercase letters and spaces.
function isAnagram (string1, string2) {
// These arrays will collect the counts.
var arr1 = [], arr2 = [];
var i = 0;
// One loop to traverse both strings.
// This loop will run n times, where n is the length of the longest string.
while (i < string1.length || i < string2.length) {
// It could happen that 'i' increases beyond the length of one of the two strings so first I check if there is a character at this index in the strings, and if this character is not a space. If it is a space it will just jump this character.
if (string1.charAt(i) != '' && string1.charAt(i) != ' ') {
// Then I increase the count for this character in the corresponding array.
// The first time a character occurs I asign 1, the next times I increase 1.
if (arr1[string1.charCodeAt(i)]) {
arr1[string1.charCodeAt(i)] += 1;
}
else {
arr1[string1.charCodeAt(i)] = 1;
}
}
// Do the same for the other string.
if (string2.charAt(i) != '' && string2.charAt(i) != ' ') {
if (arr2[string2.charCodeAt(i)]) {
arr2[string2.charCodeAt(i)] += 1;
}
else {
arr2[string2.charCodeAt(i)] = 1;
}
}
// Increase 'i'
i++;
}
// After the loop I compare the two arrays, and if they have the same counts for the same characters, the strings are anagrams.
i = ('A').charCodeAt(0); // Get the char code of the character 'A'
while (arr1[i] === arr2[i] && i <= ('Z').charCodeAt(0)) {
i++;
}
// After the loop if 'i' has increased beyond the char code of 'Z', all the counts were equal.
return (i > ('Z').charCodeAt(0) ? '1' : '0')
}
Just a reminder to please try and include a link to the code you submit in, if possible, for easier testing - this will help us test the solutions you propose and choose the best solution out of those that work.
You may still paste in raw, markdown-formatted code in your post, but we ask that you try and give us a link to your code in repl.it for ease of testing and evaluation also.
Happy coding!~CC mods
Here's my entry, using pure Javascript. My thinking is that each word or phrase is really just a set of letters, and two anagrams have matching sets of letters. My function arranges the letters so they can be compared, and then sees if they are a match.
var is_anagram = function(str1,str2){
str1 = str1.replace(/\s/g,'').toUpperCase().split('').sort().join('');
str2 = str2.replace(/\s/g,'').toUpperCase().split('').sort().join('');
if (str1 === str2){
//It is an anagram! Return 1
return "1";
}else{
//It's not a match.
return "0";
};
};
On each string: 1. remove whitespace with regex 2. convert to uppercase 3. split into an array to make it possible to sort 4. sort the array (alphabetically) 5. convert back to a string (because it's harder to compare arrays without looping)After this process, strings that are anagrams should produce the same string. If the produced strings don't match, then you don't have an anagram.
My working example is here: just saw that you prefer this so I took a few seconds to upload this
Hi everyone,
Here I present you my Python code for solving the challenge so you can read it and test it yourselves. Right after it you will find a brief explanation on how the code works and how I came up with it:
So, if you have looked at the code you would have noticed that the most substantial part is contained in the anagrams function, which contains the logic that can tell if two strings are anagrams in O(n+m).
anagrams
In order to be able to comply the time complexity constraint I assumed that both input arguments satisfied the precondition of being strings composed of uppercase ASCII letters. Then, if I wanted to accomplish the time complexity goal, I knew that I needed to iterate each argument one time at most. So, I came up with this idea of iterate over the first string and count the occurrences of each letter, and then iterate over the second string while trying to “undo” the counting I did before. This way, if the strings were actually anagrams, all my letters counts would be zero by the time I had finished iterating over the second string, and I wouldn’t have found any letter apart from the ones I encountered in the first string.
So, if we inspect the code of the anagrams function you will see that basically I use a dictionary for counting the letters occurrences. The first for loop is where I define each letter from the first word as a key in the dictionary, and I increment its value as I see them along the string:
for
for letter in first_string:
letters_count[letter] = letters_count.get(letter, 0) + 1
Later on, in the second for loop, I walk through each letter of the second string and I retrieve from the dictionary its number of occurrences:
for letter in second_string:
occurrences = letters_count.get(letter, None)
If that value is higher than 1, then I decrease it and store it back, as I already managed to match a pair of the same letter in both strings:
if occurrences > 1:
letters_count[letter] -= 1
Otherwise, if that value is exactly 1, that means I have just matched the last occurrence of that letter in the first string. Hence, I remove the letter from the dictionary as I shouldn’t be expecting to encounter this letter again while I finish my second string iteration.
if occurrences == 1:
letters_count.pop(letter, None)
Lastly, if that value is None, it means that I have found a letter that I cannot match to an occurrence of the same letter in the first string. Therefore, I can immediately conclude that the strings are note anagrams and return False:
False
if occurrences is None:
return False
By the end of the loop, if no keys are left in the dictionary (meaning that I was able to match each letter from the second string with a letter from the first string and no letter from the first string remained without match), then the words are anagrams. Otherwise, they are not.
return True if not letters_count else False
On top of that, I defined a validate_string function that runs some checks to the guarantee those assumptions I made for the anagram function inputs, and it raises some custom made exceptions in case one of those checks fails.
validate_string
anagram
Then I assembled both of the previous mentioned functions inside a wrapper function called anagram_detector, which also is responsible for translating the boolean value returned by anagram into a 1 or 0 accordingly.
anagram_detector
Finally, I added some tests cases and an interactive routine that allows the user to run the whole test suite or just type in a pair of strings for detecting if they are anagrams.
Well, that is all about the code. I hope you liked it or you find it useful.
Thanks for reading it
–
Carlos.
A post was split to a new topic: Read those docs
A post was split to a new topic: Exception handling
function isAnagram(word1, word2){
var word2Arr = word2.split("");
for(var letter of word1){
var index = word2Arr.indexOf(letter);
if(index == -1){
return "0";
}
word2Arr.splice(index,1);
}
if(word2Arr.length == 0){
return "1";
}else{
return "0";
}
}
The function isAnagram takes two arguments: word1 and word2.Then word2 gets spilled into an array of charactes called word2Arr. Then word1 gets looped through. Each letter gets queried in the word2Arr array. If a match is found, that letter gets removed from the word2Arr array. If a match is NOT found, it means word1 contains a letter that word2 does not, and is thus not an anagram of word2, and returns "0". Once the loop has finished, the length of word2Arr is checked. If all the characters have been removed (an empty array), it means the word is an anagram and "1" is returned.
My solution in Java
import java.util.Arrays;
class Input{
static int find(String x, String y){
String s1=x.replaceAll("\\s","");
String s2=y.replaceAll("\\s","");
boolean state=true;
if(s1.length()!=s2.length()){
state=false;
}else{
char[] s1Array=s1.toCharArray();
char[] s2Array=s2.toCharArray();
Arrays.sort(s1Array);
Arrays.sort(s2Array);
state=Arrays.equals(s1Array,s2Array);
}
if(state){
System.out.print("Anagrams");
return 1;
}else{
System.out.print("Not anagrams");
return 0;
}
}
}
class Anagram{
public static void main(String...s){
Input.find("TOM MARVOLO RIDDLE","I AM LORD VOLDEMORT");
}
}
Following steps are involved in the code:1. Remove the white spaces using Regex2. Convert the Strings into character arrays3. Sort the characters in the array4. Use the equals() method to check for matches5. Return "1" if they are anagrams and "0" if they are not anagrams
Since the input is guaranteed to be strings of spaces and uppercase letters, removing the spaces and comparing the sorted strings will do in Python 3:
def isanagram_slow(s1, s2):
if [a for a in sorted(s1) if a!=" "]==[b for b in sorted(s2) if b!=" "]:
return 1
return 0
# return 1 if sorted(s1)==sorted(s2) else 0
This is inefficient but compact easy version. Should whitespace be treated like any other char, the hashed line is the whole function in an even more compact form.
Intermediate difficulty version:
def isanagram(s1, s2):
A=[0 for i in range(27)]
B=[0 for i in range(27)]
# A=]
for i in s1:
if i == " ": pass
# if i == " ": A[0]+=1
else: A[ord(i)-64]+=1
for i in s2:
if i == " ": pass
# if i == " ": B[0]+=1
else: B[ord(i)-64]+=1
return 1 if A == B else 0
A & B will hold the amount of char occurencies in each string. In this case, position 0 counts spaces, others count letters. According to wikipedia, whitespaces don't count (eg "A B C" == "ABC") so I pass them, but they can be enabled by uncommenting the hashed tests.
Should list comprehension be considered to put a dent in the O(m+n) time for shorter strings, A&B arrays can be defined like the hashed examples. The code could easily be scaled to handle all the chars recognized by Python at the memory cost of 2*1,114,111 bytes (valid chr() range according to docs) for the A & B arrays.
Explanations are in comments.
Hi, my first challenge Solution on python:
def anagram_tester(s1,s2):
if len(s1)!=len(s2):
return 0
s = [0]*23
for a in s1:
s[ord(a)-ord('A')]+=1
for a in s2:
s[ord(a)-ord('A')]-=1
if s[ord(a)-ord('A')]<0:
return 0
if sum(s)==0:
return 1
else:return 0
s1,s2 = "ANAGRAMANAGRAMAMANAGR","RAMANAGRGRAMANAGAMANA"
print ("Anagram? %d" % anagram_tester(s1,s2))
It’s basically creating a list of the number of presences of each letter and increment on the first word and decrement on the second, the result should be that first there’s no negative numbers, and second the sum should be zero.
Any comments appreciated.
Link to Python code on repl.it:Anagram Tester from Anupama.
Explanation:
# 1) if length of the two strings do not match, then the strings are NOT anagrams. Stop checking. (iteration = 1) # 2) if the number of unique letters in the two strings are NOT equal, then strings are NOT anagrams. Stop checking. (iteration = 2) # 3) Convert to upper case and Sort the strings. The two strings should match at every index. If not, they are not anagrams. Stop checking. (iteration = 2 + length(string1) )
Raw code:
def anagramfn(a, b, strflag):
if(len(a) != len(b) ):
strflag = strflag + 1
elif len(''.join(sorted(set(a.lower()))) ) != len(''.join(sorted(set(a.lower()))) ):
strflag = strflag + 1
else:
a = a.upper()
a = ''.join(sorted(a))
b = b.upper()
b = ''.join(sorted(b))
ptr = 0
while(ptr < len(a)):
if(a[ptr] != b[ptr]):
strflag = strflag + 1
ptr = ptr + 1
if strflag > 0:
print("NOT Anagrams")
else :
print("Anagrams")
return;
# initialize test strings:
a = 'practi ce'
b = 'ce racpti;'
# initialize flag to indicate whether the two strings are anagrams or not.
# strflag = 1 implies the strings are true anagrams.
strflag = 0
# accept the two strings:
print("Anagram Tester")
a = input("Input String1: ")
b = input("Input String2: ")
anagramfn(a, b, strflag) ;
A post was split to a new topic: Validation for incorrect inputs
Like last week, I thought I would take a slightly more functional approach to this challenge, and like most people, I figured comparing two sorted lists is the way to go. While a lot of people just used Python’s sorted() function, I figured that if I want to make things more interesting, I could implement my own quicksort function. The quicksort I used is inspired by the elegant Haskell implementation of quicksort. Here it is:
Now for a quick explanation:
First, I define the quickSort function, which takes a pivot (the first element in a word or list) and then creates two lists, one of which contains all the values in the list after the pivot greater than or equal to the pivot, and one of those values less than the pivot. Then, it puts the pivot between these lists and sorts both of these lists using the same method recursively.
The actual anagram function is pretty straightforward. All that this does is convert the supplied words into a usable format, sorts them, and compares them to see if they are the same. If they are, then they are anagrams, otherwise they are not.
Finally, let’s talk about efficiency. I realize that this is definitely not O(M + N), since it uses quicksort, which is at best O(NlogN). This program is probably slower than this, though, due to the other stuff involved, but the purpose of this exercise for me is to practice my functional programming skills with Python, so I don’t mind the slowness.
Note: here is the wikipedia article on quicksort for anyone looking to read about it in more depth
A post was merged into an existing topic: Validation for incorrect inputs
A solution in Python which has a O(n+m) time complexity. It iterates through the first string and counts up the occurences of each character, and then does the same for the second string but decrements the count instead. If the two strings are anagrams then the count for every character should be 0.
Decided to handle all 128 ASCII codes so that the function works with all ASCII characters and not just capital letters, and it removes the need to subtract a base value from each of the ASCII values to convert it to a 0-based index.
def is_anagram(s1, s2):
# can return 0 immediately if the strings are different lengths
if len(s1) != len(s2):
return 0
# for counting the ASCII characters 0 to 127
counts = [0]*128
# increment the count for each character in the first string
for c in s1:
counts[ord(c)] += 1
# decrement the count for each character in the second string
for c in s2:
counts[ord(c)] -= 1
# the strings are anagrams if all the counts cancel each other out
return 0 if any(counts) else 1
There is a simple optimisation to check that the strings are the same length at the start of the function; if the strings are different lengths then they cannot be anagrams. Would be significant improvement for very big strings.
A totally inconsequential optimisation (but why not) is the use of the any() function instead of sum(). It is ever so slightly faster as it only needs to do a comparison with 0 instead of addition, and it does lazy evaluation, meaning it will return as soon as a non-zero value is found.
%timeit sum([0]*128)
100000 loops, best of 3: 2.48 µs per loop
%timeit any([0]*128)
100000 loops, best of 3: 2.07 µs per loop
%timeit sum([1]*128)
100000 loops, best of 3: 2.47 µs per loop
%timeit any([1]*128)
1000000 loops, best of 3: 764 ns per loop
Out of interest, I compared the runtime with a solution that use sorting to compare the strings (shown below). The time complexity for sorting is O(n log(n)), but for short strings the function below is faster. The point where the function above is faster is about strings of length 70 on my laptop.
def is_anagram(s1, s2):
return 1 if len(s1) == len(s2) and sorted(s1) == sorted(s2) else 0
I had this idea as well, but I don't think it works! Just adding up the ASCII values would mean it would see these two strings as anagrams, "AD" and "BC".
I thought maybe you can use the product but it would only work if each letter was represented by a prime number and the calculation of that product would probably make the function slow compared to the other methods, especially for large strings.
Here is my entry using Python 3.6.1 hosted on repl.it:
My first bit of thinking was to be sure to get the input from the user and prompt them as to what words they would like to compare. I then assigned another set of variables equal to the original input ran through the built-in .upper() function, to guarantee that the function would be handling uppercase letters, as per the challenge rules. Next up was converting the strings into lists with a for loop to iterate through each of the words and append each iterated item to the appropriate list. After assigning the lists to sorted versions of themselves, I then compared the sorted lists to each other and returned 1 for anagrams, and 0 for not anagrams.
Code below for those who do not wish to follow links:
def anagram():
#ask the user for words to compare
print('What two words would you like to compare and see if they are anagrams?')
print('First word: ')
word1 = str(input())
print('Second word: ')
word2 = str(input())
#converts the strings from the user to uppercase
word1Upper = word1.upper()
word2Upper = word2.upper()
#creation of empty lists for conversion from strings to lists
word1u = []
word2u = []
#for loops do the work of making lists from the strings
for char in word1Upper:
word1u.append(char)
for char in word2Upper:
word2u.append(char)
#sorting the letters into sequential order so that Python can compare the lists
word1u = sorted(word1u)
word2u = sorted(word2u)
#condition that compares the sorted lists to each other to see if they match
if word1u == word2u:
#returns 1 if they match
""" print('anagram')"""
return 1
else:
""" print('not an anagram')"""
#returns 0 if they don't
return 0
#print(word1u, word2u)
Time complexity was not taken into consideration when devising this solution as I’m still definitely a beginner.
Here is my simple code in PHP.
<?php
function find_anagram ($sample_string1, $sample_string2)
{
$string1 = str_replace(' ', '', $sample_string1);
$string2 = str_replace(' ', '', $sample_string2);
$str_len1 = strlen($string1);
$str_len2 = strlen($string2);
$flag=1;
if($str_len1!=$str_len2)
{
$flag=0;
}
else {
$c = $str_len2-1;
for($i = 0; $i<$str_len1; $i++)
{
If ($string1[$i] != $string2[$c])
{
$flag=0;
break;
}
$c--;
}
}
echo $flag . "<br />";
}
find_anagram("amma", "amma");
find_anagram("asdf", "asdf");
?> | https://discuss.codecademy.com/t/challenge-anagram-detector/83127/19 | CC-MAIN-2017-39 | refinedweb | 3,337 | 69.52 |
0
I found that in python we have no realy private attributes.we just can use _ or __.but these are not deny access to my attributes.some thing such as private variables in c++.
Is it TRUE? Realy python is week in these?
I found that in python we have no realy private attributes.we just can use _ or __.but these are not deny access to my attributes.some thing such as private variables in c++.
Is it TRUE? Realy python is week in these?
Go ahead and test it!
If you can't live with the amount of protection given, use C++.
Edited 6 Years Ago by vegaseat: n/a
It is in fact true. Nothing is truly private in Python. What happens is that Python alters the name of the variable internally.
>>> class Foo:>> Foo.__privatebar Traceback (most recent call last): File "<pyshell#3>", line 1, in <module> Foo.__privatebar AttributeError: class Foo has no attribute '__privatebar' >>> Foo._Foo__privatebar 'HelloWorld!' >>>
But PLEASE! Do not ever do this. Just imagine that the python god will come and hit you if you do this.
This is not weak. Python doesn't encourage bad code, but they don't deny it. If you want to do something stupid like this, don't come here to ask us to debug it for you.
Edited 6 Years Ago by ultimatebuster: n/a
To confuse variable Foo.__privatebar with Foo._Foo__privatebar would be a hard thing to do. As you can see, Python uses name mangling to protect a private variable.
I tried to say my friend that python is as powerful as java.but they said me this problem.and the other was java's machine.it wor4k on every thing but python...
I don't know.I am using python since 2 years.I choosed it and I LOVE IT.
But we have to understand python's abilities.is not True.
There really are good reasons to prefer one language or another for a particular task. There is no good way to make a general decision about what language is 'better' than another without more specification.
This (I think it is silly) discussion seems to be a theme for the last few days. End of term syndrome??
Direct hardware access is not Python's great strength, but yes, it is possible using the
ctypes module, or if you really want it your way, by providing a C or C++ extension.
When I started as a C++ programmer coming from C, I thought that having private, protected and public class members gave you a lot of good control over the way your classes were used. The longer I worked with C++ (and as I learned and began using Java), the more I found that I wanted to give the users of my class more not less control. Yes, it is good to have accessors, so you can decorate or instrument them if for no other reason, but if you don't trust the 'downstream users' to do the right thing, you end up spending way too much time armor plating your code. As I now see it, you document document document, but you don't lock things up. This may be partly because now I'm informed by the way Python does things, but I think it is also a life lesson learned.
In my opinion, Python's strengths are:
... but It is neither small nor fast, so it doesn't belong where small or fast matters more than quick and easy from the developer's perspective. Though it is good as the user interface layer above optimized code that does the heavy lifting.?
Yes, Python has private attributes, but it uses "name mangling" to implement it. For all practical purposes this is good enough!
Beg to differ with sneekula: Python has a coding idiom that mangles the names of members whose unmangled name begins with __, but that mangling does not make them private. However, I agree that "For all practical purposes this is good enough."
Private attributes are stupid for dynamic languages.
Don't you see Python is dynamic and strongly typed,
and C++ is dynamic and strongly typed?
Python doesn't have them for a reason.
It contributes to the beauty of the Python language.
So in other words, it is a feature.
Even private attributes in static languages are not absolutely private.
In C#, I know that you can use Reflection to use private methods from another class.
Edited 6 Years Ago by jcao219: n/a
jcao219's post confuses me: Python and C++ share "dynamic" and "strongly typed" but C# is apparently "static" with no mention of type. Perhaps jcao219 could re-post using more usual terminology?
I agree that the lack of private and protected in Python is a feature, but perhaps not for the same reasons: I like it because it promotes the use of Python to do its own introspection for things like serialization and debugging, things which are harder to do in languages that try to control access to some class members. And that 'eat your own dog food' effect is something that I do see as elegant / beautiful.
Whoops, I made a mistake.
C++ is static. | https://www.daniweb.com/programming/software-development/threads/285375/private-attributes-in-python | CC-MAIN-2016-50 | refinedweb | 877 | 75.91 |
.
Interview Questions on Java
What if the main method is declared as private?
The[])?
main(..) is the first method called by java environment when a program is executed so it has to accessible from java environment. Hence the access specifier has to be public.() ?
Or
what is difference between == and equals
Or
Difference between == and equals method
Or
What would you use to compare two String variables – the operator == or the method equals()?
Or.
Output
== comparison : true
== comparison : true
Using equals method : true
false
Using equals method : true
What if the static modifier is removed from the signature of the main method?
Or?
Or
What is final, finalize() and finally?
Or
What is finalize() method?
Or
What is the difference between final, finally and finalize?
Or?
Global variables are globally accessible. Java does not support globally accessible variables due to following reasons:
- The global variables breaks the referential transparency
- Global variables creates collisions in namespace.
How to convert String to Number in java program?
The valueOf() function of Integer class is is used to convert string to Number. Here is the code example:
String numString = “1000″;
Or.
Example?
Or
What is the difference between public, private, protected and default Access Specifiers?
Or?
Or
What are class variables?
Or
What is static in java?
Or.
There are several classes like String which we use in program but we do not import it. Why?
String is a part of “java.lang” package and this package gets loaded by default by the Java Virtual Machine so we need not to import it. If we import it explicitly, there is no harm in doing that. ‘get’ and ‘set’.
What is the difference between JDK and JRE and JVM?.
Explain the flow of writing the java code to run?
We develop the java program using Java development kit (JDK) and then compile it using “javac” command which is also a part of JDK. Result of javac command is the .class file which is a byte code and is platform independent. When we say byte code is platform independent, it means that we can use the same .class file on any operating system. When it comes to run, we use java command which is a part of JRE. JRE processes the byte code and result is being used by JVM which converts the byte code to machine readable code.
What are the environment variables required to be set to run a java program?
- JAVA_HOME- set it to the root location of java
- PATH- set it to the bin directory of java location.
What are some of the advantages of Java?
- Java is an Object Oriented language.
- Java comes with built-in support of several features like garbage collection, multi threading, socket programming etc.
- Java is platform independent.
What are the key differences between C and Java?
There are several differences between java and C. Key differences are-
- Java does not support multiple inheritance instead it supports multi-level inheritance which means in java any class cannot inherit to multiple classes.
- There is no concept of pointers in java.
- Java does not support unions and structures and destructors.
- Java includes built-in support of memory management via garbage collections where as in C, developer has to take care of it.
What is POJO and what are its advantages?
POJO stands for Plain Java Object which promotes encapsulation and is always recommended. POJO has certain rules-
- All member variables should be declared as private so that they are not accessible to the outer world directly.
- Corresponding to each member variable, there will be a getter/setter public method which will be used to get or set the values.
- Naming convention of getter methods will be getXXX() where XXX is the name of variable with first character in upper case.
- Naming convention of setter methods will be setXXX() where XXX is the name of variable with first character in upper case.
The biggest advantage of POJO is encapsulation. Let’s take an example.
We have one class Account which has a member variable “balance”. If we have directly exposed this variable then other code can set it as negative value which is not correct. But we can handle it via setter methods and can have a check in setter to set it 0 if any code is trying to set negative value.
Can I change the argument name of main method to something else?
Yes we can change. Its only we cannot change the signature. Until the argument type is array of String we can use any name. Below is the example of valid main method.
public static void main(String[] xyz)
Can we have a main method in multiple classes?
Yes we can have main method in multiple classes. Class whose name we have passed while running the application will be executed. For example we have two classes ClassA and ClassB and both are having main() method than if we call java ClassA , main method of ClassA will be executed and on calling java ClassB, main of ClassB will be executed.
If we do not provide any arguments to main method while running from command prompt, what will be the value of string array?
It will be an empty array and not null. To validate this, we can simply print the length of argument using args.length and it will print 0. If it was a null, we would have got Null pointer exception.
What will happen if we import the same package multiple times?
Program will compile and run successfully. Internally JVM loads it only once.
Will using a * in import statement import all child packages?
No. * will import all the classes of the given package and will not import classes of child packages. For example, we have below 4 classes
- com.example.A
- com.example.B
- com.example.java.C
- com.example.java.D
using a import com.example.* will import com.example.A and com.example.B and not the classes of java child package.
What will happen if we remove the “static” keyword from main method?
Code will compile fine but on running we will get “NoSuchMethodError” because JVM will look for static method as running static method does not require any instance of a class.
Name the class which is the parent of every class in Java?
java.lang.Object
What will happen if I write multiple public class in same java file?
Java file will not compile as we can have only one public class in Java file. Rest all classes have to be non-public. Also the name of java file has to be same as that of public class.
Is Java pure Object Oriented programming language?
No, Java is not pure objected oriented programming language because it does support 8 primitive data types (char, byte, int, long, double, float, short, boolean).
Explain different primitive data types of java?
There are 8 primitive data types supported by java.
- byte- it is 8 bit signed and its default value is 0 and minimum value is -128 (-2^7) and maximum value is 127 (2^7-1)
- short- it is 16 bit signed its default value is 0 and minimum value is -32768 (-2^15) and maximum value is 32767 (2^15-1)
- int- it is 32 bit signed with default value as 0. Minimum value is - 2147483648 (-2^31) and maximum value is - 2147483647 (2^31-1)
- long- it is 64 bit signed with default value as 0. Minimum value is -9223372036854775808 (-2^63) and maximum value is 9223372036854775807 (2^63-1)
- float- is 32-bit IEEE 754 floating point with default value as 0.0f
- double- is 64-bit IEEE 754 floating point with default value as 0.0d
- boolean- represents one bit and default value as false. Memory consumed by boolean is platform dependent.
- char- is 16 bit Unicode character with minimum value as 0 (\u0000) and maximum value as 65535 (\uffff) | http://www.wideskills.com/java-interview-questions/java-interview-questions | CC-MAIN-2020-16 | refinedweb | 1,322 | 66.23 |
Goals:
Teach through minimal targeted functional/useful/non-abstract examples (e.g.
@swap or
@assert) that introduce concepts in suitable contexts
Prefer to let the code illustrate/demonstrate the concepts rather than paragraphs of explanation
Avoid linking 'required reading' to other pages -- it interrupts the narrative
Present things in a sensible order that will making learning easiest
Resources:
julialang.org
wikibook (@Cormullion)
5 layers (Leah Hanson)
SO-Doc Quoting (@TotalVerb)
SO-Doc -- Symbols that are not legal identifiers (@TotalVerb)
SO: What is a Symbol in Julia (@StefanKarpinski)
Discourse thread (@p-i-) Metaprogramming
Most of the material has come from the discourse channel, most of that has come from fcard... please prod me if I had forgotten attributions.
julia> mySymbol = Symbol("myName") # or 'identifier' :myName julia> myName = 42 42 julia> mySymbol |> eval # 'foo |> bar' puts output of 'foo' into 'bar', so 'bar(foo)' 42 julia> :( $mySymbol = 1 ) |> eval 1 julia> myName 1
Passing flags into functions:
function dothing(flag) if flag == :thing_one println("did thing one") elseif flag == :thing_two println("did thing two") end end julia> dothing(:thing_one) did thing one julia> dothing(:thing_two) did thing two
A hashkey example:
number_names = Dict{Symbol, Int}() number_names[:one] = 1 number_names[:two] = 2 number_names[:six] = 6
(Advanced)
(@fcard)
:foo a.k.a.
:(foo) yields a symbol if
foo is a valid identifier, otherwise an expression.
# NOTE: Different use of ':' is: julia> :mySymbol = Symbol('hello world') #(You can create a symbol with any name with Symbol("<name>"), # which lets us create such gems as: julia> one_plus_one = Symbol("1 + 1") Symbol("1 + 1") julia> eval(one_plus_one) ERROR: UndefVarError: 1 + 1 not defined ... julia> valid_math = :($one_plus_one = 3) :(1 + 1 = 3) julia> one_plus_one_plus_two = :($one_plus_one + 2) :(1 + 1 + 2) julia> eval(quote $valid_math @show($one_plus_one_plus_two) end) 1 + 1 + 2 = 5 ...
Basically you can treat Symbols as lightweight strings. That's not what they're for, but you can do it, so why not. Julia's Base itself does it,
print_with_color(:red, "abc") prints a red-colored abc .
(Almost) everything in Julia is an expression, i.e. an instance of
Expr, which will hold an AST.
# when you type ... julia> 1+1 2 # Julia is doing: eval(parse("1+1")) # i.e. First it parses the string "1+1" into an `Expr` object ... julia> ast = parse("1+1") :(1 + 1) # ... which it then evaluates: julia> eval(ast) 2 # An Expr instance holds an AST (Abstract Syntax Tree). Let's look at it: julia> dump(ast) Expr head: Symbol call args: Array{Any}((3,)) 1: Symbol + 2: Int64 1 3: Int64 1 typ: Any # TRY: fieldnames(typeof(ast)) julia> :(a + b*c + 1) == parse("a + b*c + 1") == Expr(:call, :+, :a, Expr(:call, :*, :b, :c), 1) true
Nesting
Exprs:
julia> dump( :(1+2/3) ) Expr head: Symbol call args: Array{Any}((3,)) 1: Symbol + 2: Int64 1 3: Expr head: Symbol call args: Array{Any}((3,)) 1: Symbol / 2: Int64 2 3: Int64 3 typ: Any typ: Any # Tidier rep'n using s-expr julia> Meta.show_sexpr( :(1+2/3) ) (:call, :+, 1, (:call, :/, 2, 3))
Exprs using
quote
julia> blk = quote x=10 x+1 end quote # REPL[121], line 2: x = 10 # REPL[121], line 3: x + 1 end julia> blk == :( begin x=10; x+1 end ) true # Note: contains debug info: julia> Meta.show_sexpr(blk) (:block, (:line, 2, Symbol("REPL[121]")), (:(=), :x, 10), (:line, 3, Symbol("REPL[121]")), (:call, :+, :x, 1) ) # ... unlike: julia> noDbg = :( x=10; x+1 ) quote x = 10 x + 1 end
... so
quote is functionally the same but provides extra debug info.
(*) TIP: Use
let to keep
x within the block
quote-ing a
quote
Expr(:quote, x) is used to represent quotes within quotes.
Expr(:quote, :(x + y)) == :(:(x + y)) Expr(:quote, Expr(:$, :x)) == :(:($x))
QuoteNode(x) is similar to
Expr(:quote, x) but it prevents interpolation.
eval(Expr(:quote, Expr(:$, 1))) == 1 eval(QuoteNode(Expr(:$, 1))) == Expr(:$, 1)
(Disambiguate the various quoting mechanisms in Julia metaprogramming
:(foo) means "don't look at the value, look at the expression"
$foo means "change the expression to its value"
:($(foo)) == foo.
$(:(foo)) is an error.
$(...) isn't an operation and doesn't do anything by itself, it's an "interpolate this!" sign that the quoting syntax uses. i.e. It only exists within a quote.
$
foothe same as
eval(
foo
)?
No!
$foo is exchanged for the compile-time value
eval(foo) means to do that at runtime
eval will occur in the global scope
interpolation is local
eval(:<expr>) should return the same as just
<expr> (assuming
<expr> is a valid expression in the current global space)
eval(:(1 + 2)) == 1 + 2 eval(:(let x=1; x + 1 end)) == let x=1; x + 1 end
macros
Ready? :)
# let's try to make this! julia> x = 5; @show x; x = 5
@showmacro:
macro log(x) :( println( "Expression: ", $(string(x)), " has value: ", $x ) ) end u = 42 f = x -> x^2 @log(u) # Expression: u has value: 42 @log(42) # Expression: 42 has value: 42 @log(f(42)) # Expression: f(42) has value: 1764 @log(:u) # Expression: :u has value: u
expandto lower an
Expr
5 layers (Leah Hanson) <-- explains how Julia takes source code as a string, tokenizes it into an
Expr-tree (AST), expands out all the macros (still AST), lowers (lowered AST), then converts into LLVM (and beyond -- at the moment we don't need to worry what lies beyond!)
Q:
code_lowered acts on functions. Is it possible to lower an
Expr?
A: yup!
# function -> lowered-AST julia> code_lowered(*,(String,String)) 1-element Array{LambdaInfo,1}: LambdaInfo template for *(s1::AbstractString, ss::AbstractString...) at strings/basic.jl:84 # Expr(i.e. AST) -> lowered-AST julia> expand(:(x ? y : z)) :(begin unless x goto 3 return y 3: return z end) julia> expand(:(y .= x.(i))) :((Base.broadcast!)(x,y,i)) # 'Execute' AST or lowered-AST julia> eval(ast)
If you want to only expand macros you can use
macroexpand:
# AST -> (still nonlowered-)AST but with macros expanded: julia> macroexpand(:(@show x)) quote (Base.println)("x = ",(Base.repr)(begin # show.jl, line 229: #28#value = x end)) #28#value end
...which returns a non-lowered AST but with all macros expanded.
esc()
esc(x) returns an Expr that says "don't apply hygiene to this", it's the same as
Expr(:escape, x). Hygiene is what keeps a macro self-contained, and you
esc things if you want them to "leak". e.g.
swapmacro to illustrate
esc()
macro swap(p, q) quote tmp = $(esc(p)) $(esc(p)) = $(esc(q)) $(esc(q)) = tmp end end x,y = 1,2 @swap(x,y) println(x,y) # 2 1
$ allows us to 'escape out of' the
quote.
So why not simply
$p and
$q? i.e.
# FAIL! tmp = $p $p = $q $q = tmp
Because that would look first to the
macro scope for
p, and it would find a local
p i.e. the parameter
p (yes, if you subsequently access
p without
esc-ing, the macro considers the
p parameter as a local variable).
So
$p = ... is just a assigning to the local
p. it's not affecting whatever variable was passed-in in the calling context.
Ok so how about:
# Almost! tmp = $p # <-- you might think we don't $(esc(p)) = $q # need to esc() the RHS $(esc(q)) = tmp
So
esc(p) is 'leaking'
p into the calling context. "The thing that was passed into the macro that we receive as
p"
julia> macro swap(p, q) quote tmp = $p $(esc(p)) = $q $(esc(q)) = tmp end end @swap (macro with 1 method) julia> x, y = 1, 2 (1,2) julia> @swap(x, y); julia> @show(x, y); x = 2 y = 1 julia> macroexpand(:(@swap(x, y))) quote # REPL[34], line 3: #10#tmp = x # REPL[34], line 4: x = y # REPL[34], line 5: y = #10#tmp end
As you can see
tmp gets the hygiene treatment
#10#tmp, whereas
x and
y don't.
Julia is making a unique identifier for
tmp, something you can manually do with
gensym, ie:
julia> gensym(:tmp) Symbol("##tmp#270")
But: There is a gotcha:
julia> module Swap export @swap macro swap(p, q) quote tmp = $p $(esc(p)) = $q $(esc(q)) = tmp end end end Swap julia> using Swap julia> x,y = 1,2 (1,2) julia> @swap(x,y) ERROR: UndefVarError: x not defined
Another thing julia's macro hygiene does is, if the macro is from another module, it makes any variables (that were not assigned inside the macro's returning expression, like
tmp in this case) globals of the current module, so
$p becomes
Swap.$p, likewise
$q ->
Swap.$q.
In general, if you need a variable that is outside the macro's scope you should esc it, so you should
esc(p) and
esc(q) regardless if they are on the LHS or RHS of a expression, or even by themselves.
people have already mentioned
gensyms a few times and soon you will be seduced by the dark side of defaulting to escaping the whole expression with a few
gensyms peppered here and there, but... Make sure to understand how hygiene works before trying to be smarter than it! It's not a particularly complex algorithm so it shouldn't take too long, but don't rush it! Don't use that power until you understand all the ramifications of it... (@fcard)
untilmacro
(@Ismael-VC)
"until loop" macro until(condition, block) quote while ! $condition $block end end |> esc end julia> i=1; @until( i==5, begin; print(i); i+=1; end ) 1234
(@fcard)
|> is controversial, however. I am surprised a mob hasn't come to argue yet. (maybe everyone is just tired of it). There is a recommendation of having most if not all of the macro just be a call to a function, so:
macro until(condition, block) esc(until(condition, block)) end function until(condition, block) quote while !$condition $block end end end
...is a safer alternative.
##@fcard's simple macro challenge
Task: Swap the operands, so
swaps(1/2) gives
2.00 i.e.
2/1
macro swaps(e) e.args[2:3] = e.args[3:-1:2] e end @swaps(1/2) 2.00
More macro challenges from @fcard here
assertmacro
macro assert(ex) return :( $ex ? nothing : throw(AssertionError($(string(ex)))) ) end
Q: Why the last
$?
A: It interpolates, i.e. forces Julia to
eval that
string(ex) as execution passes through the invocation of this macro.
i.e. If you just run that code it won't force any evaluation. But the moment you do
assert(foo) Julia will invoke this macro replacing its 'AST token/Expr' with whatever it returns, and the
$ will kick into action.
(@fcard) I don't think there is anything technical keeping
{} from being used as blocks, in fact one can even pun on the residual
{} syntax to make it work:
julia> macro c(block) @assert block.head == :cell1d esc(quote $(block.args...) end) end @c (macro with 1 method) julia> @c { print(1) print(2) 1+2 } 123
*(unlikely to still work if/when the {} syntax is repurposed)
So first Julia sees the macro token, so it will read/parse tokens until the matching
end, and create what? An
Expr with
.head=:macro or something? Does it store
"a+1" as a string or does it break it apart into
:+(:a, 1)? How to view?
?
(@fcard) In this case because of lexical scope, a is undefined in
@Ms scope so it uses the global variable...
I actually forgot to escape the flipplin' expression in my dumb example, but the "only works within the same module" part of it still applies.
julia> module M macro m() :(a+1) end end M julia> a = 1 1 julia> M.@m ERROR: UndefVarError: a not defined
The reason being that, if the macro is used in any module other than the one it was defined in, any variables not defined within the code-to-be-expanded are treated as globals of the macro's module.
julia> macroexpand(:(M.@m)) :(M.a + 1)
###@Ismael-VC
@eval begin "do-until loop" macro $(:do)(block, until::Symbol, condition) until ≠ :until && error("@do expected `until` got `$until`") quote let $block @until $condition begin $block end end end |> esc end end julia> i = 0 0 julia> @do begin @show i i += 1 end until i == 5 i = 0 i = 1 i = 2 i = 3 i = 4
""" Internal function to return captured line number information from AST ##Parameters - a: Expression in the julia type Expr ##Return - Line number in the file where the calling macro was invoked """ _lin(a::Expr) = a.args[2].args[1].args[1] """ Internal function to return captured file name information from AST ##Parameters - a: Expression in the julia type Expr ##Return - The name of the file where the macro was invoked """ _fil(a::Expr) = string(a.args[2].args[1].args[2]) """ Internal function to determine if a symbol is a status code or variable """ function _is_status(sym::Symbol) sym in (:OK, :WARNING, :ERROR) && return true str = string(sym) length(str) > 4 && (str[1:4] == "ERR_" || str[1:5] == "WARN_" || str[1:5] == "INFO_") end """ Internal function to return captured error code from AST ##Parameters - a: Expression in the julia type Expr ##Return - Error code from the captured info in the AST from the calling macro """ _err(a::Expr) = (sym = a.args[2].args[2] ; _is_status(sym) ? Expr(:., :Status, QuoteNode(sym)) : sym) """ Internal function to produce a call to the log function based on the macro arguments and the AST from the ()->ERRCODE anonymous function definition used to capture error code, file name and line number where the macro is used ##Parameters - level: Loglevel which has to be logged with macro - a: Expression in the julia type Expr - msgs: Optional message ##Return - Statuscode """ function _log(level, a, msgs) if isempty(msgs) :( log($level, $(esc(:Symbol))($(_fil(a))), $(_lin(a)), $(_err(a)) ) else :( log($level, $(esc(:Symbol))($(_fil(a))), $(_lin(a)), $(_err(a)), message=$(esc(msgs[1]))) ) end end macro warn(a, msgs...) ; _log(Warning, a, msgs) ; end
(@p-i-) Suppose I just do
macro m(); a+1; end in a fresh REPL. With no
a defined. How can I ‘view’ it?
like, is there some way to ‘dump’ a macro?
Without actually executing it
(@fcard) All the code in macros are actually put into functions, so you can only view their lowered or type-inferred code.
julia> macro m() a+1 end @m (macro with 1 method) julia> @code_typed @m LambdaInfo for @m() :(begin return Main.a + 1 end) julia> @code_lowered @m CodeInfo(:(begin nothing return Main.a + 1 end)) # ^ or: code_lowered(eval(Symbol("@m")))[1] # ouf!
Other ways to get a macro's function:
julia> macro getmacro(call) call.args[1] end @getmacro (macro with 1 method) julia> getmacro(name) = getfield(current_module(), name.args[1]) getmacro (generic function with 1 method) julia> @getmacro @m @m (macro with 1 method) julia> getmacro(:@m) @m (macro with 1 method)
julia> eval(Symbol("@M")) @M (macro with 1 method) julia> dump( eval(Symbol("@M")) ) @M (function of type #@M) julia> code_typed( eval(Symbol("@M")) ) 1-element Array{Any,1}: LambdaInfo for @M() julia> code_typed( eval(Symbol("@M")) )[1] LambdaInfo for @M() :(begin return $(Expr(:copyast, :($(QuoteNode(:(a + 1)))))) end::Expr) julia> @code_typed @M LambdaInfo for @M() :(begin return $(Expr(:copyast, :($(QuoteNode(:(a + 1)))))) end::Expr)
^ looks like I can use
code_typed instead
eval(Symbol("@M"))?
(@fcard) Currently, every macro has a function associated with it. If you have a macro called
M, then the macro's function is called
@M. Generally you can get a function's value with e.g.
eval(:print) but with a macro's function you need to do
Symbol("@M"), since just
:@M becomes an
Expr(:macrocall, Symbol("@M")) and evaluating that causes a macro-expansion.
code_typeddisplay params?
(@p-i-)
julia> code_typed( x -> x^2 )[1] LambdaInfo for (::##5#6)(::Any) :(begin return x ^ 2 end)
^ here I see one
::Any param, but it doesn't seem to be connected with the token
x.
julia> code_typed( print )[1] LambdaInfo for print(::IO, ::Char) :(begin (Base.write)(io,c) return Base.nothing end::Void)
^ similarly here; there is nothing to connect
io with the
::IO
So surely this can't be a complete dump of the AST representation of that particular
(@fcard)
print(::IO, ::Char) only tells you what method it is, it's not part of the AST.
It isn't even present in master anymore:
julia> code_typed(print)[1] CodeInfo(:(begin (Base.write)(io,c) return Base.nothing end))=>Void
(@p-i-) I don't understand what you mean by that. It seems to be dumping the AST for the body of that method, no?
I thought
code_typed gives the AST for a function. But it seems to be missing the first step, i.e. setting up tokens for params.
(@fcard)
code_typed is meant to only show the body's AST, but for now it does give the complete AST of the method, in the form of a
LambdaInfo (0.5) or
CodeInfo (0.6), but a lot of the information is omitted when printed to the repl. You will need to inspect the
LambdaInfo field by field in order to get all the details.
dump is going to flood your repl, so you could try:
macro method_info(call) quote method = @code_typed $(esc(call)) print_info_fields(method) end end function print_info_fields(method) for field in fieldnames(typeof(method)) if isdefined(method, field) && !(field in [Symbol(""), :code]) println(" $field = ", getfield(method, field)) end end display(method) end print_info_fields(x::Pair) = print_info_fields(x[1])
Which gives all the values of the named fields of a method's AST:
julia> @method_info print(STDOUT, 'a') rettype = Void sparam_syms = svec() sparam_vals = svec() specTypes = Tuple{Base.#print,Base.TTY,Char} slottypes = Any[Base.#print,Base.TTY,Char] ssavaluetypes = Any[] slotnames = Any[Symbol("#self#"),:io,:c] slotflags = UInt8[0x00,0x00,0x00] def = print(io::IO, c::Char) at char.jl:45 nargs = 3 isva = false inferred = true pure = false inlineable = true inInference = false inCompile = false jlcall_api = 0 fptr = Ptr{Void} @0x00007f7a7e96ce10 LambdaInfo for print(::Base.TTY, ::Char) :(begin $(Expr(:invoke, LambdaInfo for write(::Base.TTY, ::Char), :(Base.write), :(io), :(c))) return Base.nothing end::Void)
See the lil'
def = print(io::IO, c::Char)? There you go! (also the
slotnames = [..., :io, :c] part)
Also yes, the difference in output is because I was showing the results on master.
(@Ismael-VC) you mean like this? Generic dispatch with Symbols
You can do it this way:
julia> function dispatchtest{alg}(::Type{Val{alg}}) println("This is the generic dispatch. The algorithm is $alg") end dispatchtest (generic function with 1 method) julia> dispatchtest(alg::Symbol) = dispatchtest(Val{alg}) dispatchtest (generic function with 2 methods) julia> function dispatchtest(::Type{Val{:Euler}}) println("This is for the Euler algorithm!") end dispatchtest (generic function with 3 methods) julia> dispatchtest(:Foo) This is the generic dispatch. The algorithm is Foo julia> dispatchtest(:Euler)
This is for the Euler algorithm! I wonder what does @fcard thinks about generic symbol dispatch! ---^ :angel:
@def m begin a+2 end @m # replaces the macro at compile-time with the expression a+2
More accurately, only works within the toplevel of the module the macro was defined in.
julia> module M macro m1() a+1 end end M julia> macro m2() a+1 end @m2 (macro with 1 method) julia> a = 1 1 julia> M.@m1 ERROR: UndefVarError: a not defined julia> @m2 2 julia> let a = 20 @m2 end 2
esc keeps this from happening, but defaulting to always using it goes against the language design.
A good defense for this is to keep one from using and introducing names within macros, which makes them hard to track to a human reader. | https://riptutorial.com/julia-lang/example/26313/guide | CC-MAIN-2021-25 | refinedweb | 3,288 | 59.94 |
I've been trying for a couple days to compile a native ARM Android binary that will execute on my phone using a terminal application. I want to generate the same type of binary as the standard Posix binaries installed on the phone like ls, mkdir etc. I've downloaded the Android NDK under Mac OS X and have been able to compile simple ELF binaries without errors. However, when I transfer them to the phone, they always segfault. That is, they segfault when compiled with -static in GCC. If I don't use -static, they complain about not being linked, etc. Put simply, they don't work.
My hypothesis is that they are not linking to the Android standard C library properly. Even though I am linking my binaries with the libc provided by the NDK, they still don't work. I read that Android uses the Bionic C library, and tried to download source for it but I'm not sure how to build a library from it (it's all ARM assembly, it seems).
Is it true that the Android C library on the phone is different from the one provided with the Android NDK? Will the one included with the NDK not allow me to compile native binaries I can execute through a terminal? Any guidance here is greatly appreciated!
Update:
I finally got this to work using GCC 4.7.0 on Mac OS X. I downloaded the Bionic headers and then compiled a dynamically linked binary using the C library that comes with the Android NDK. I was able to get a test app to work on the phone using the phone's C lib (the binary was 33K). I also tried to statically link against the NDK's C library, and that also worked.
In order to get this all working I had to pass -nostdlib to GCC and then manually add crtbegin_dynamic.o and crtend_android.o to GCC's command line. It works something like this:
$CC \
$NDK_PATH/usr/lib/crtbegin_dynamic.o \
hello.c -o hello \
$CFLAGS \
$NDK_PATH/usr/lib/crtend_android.o
Just use the android-ndk. And build a Android.mk like so.
include $(BUILD_EXECUTABLE) is what tells it build a executable instead of a JNI .lib
ifneq ($(TARGET_SIMULATOR),true) LOCAL_PATH:= $(call my-dir) include $(CLEAR_VARS) LOCAL_CFLAGS += -Wall LOCAL_LDLIBS := -L$(LOCAL_PATH)/lib -llog -g LOCAL_C_INCLUDES := bionic LOCAL_C_INCLUDES += $(LOCAL_PATH)/include LOCAL_SRC_FILES:= main.cpp LOCAL_MODULE := mycmd include $(BUILD_EXECUTABLE) endif # TARGET_SIMULATOR != true | https://codedump.io/share/ahlcfonQ2sdO/1/want-to-compile-native-android-binary-i-can-run-in-terminal-on-the-phone | CC-MAIN-2017-09 | refinedweb | 408 | 66.74 |
Code customization in Kentico CMS 6 Martin Hejtmanek — Oct 24, 2011 cmscodekenticokentico cms 6 Kentico CMS version 6 comes with a reviewed customization options which give you more flexibility. This article describes what the changes are and how they simplify your work. Hi there, As you may notice if you install Kentico CMS 6 and compare it to 5.5 R2, especially if you made some customizations, some significant changes happened. Every change has a trigger, so before I tell you what is different, let's see the version 5.5 R2 from a critical point of view to see what wasn't good enough. Not enough flexibility in version 5.5 R2 The heading pretty much describes it, all the items I will mention are about the overall flexibility of the solution. First of all, there was an issue that you needed to solve if you wanted to integrate Kentico CMS with an existing ASP.NET application. The issue was the Global.asax.cs file, which contained a lot of code. This caused two major problems, one was taking care about merging of the existing code and Kentico CMS code, and the other was maintaining this during upgrades and hotfixing. Another problem that we often saw was too complicated customization if you only needed a few lines of code to customize. Whether you wanted to define custom handlers for documents, modify a single method in the E-commerce provider, or write your own e-mail sending method, you always had to start with some of our sample libraries, add them to the project (which itself required Visual Studio), and compile that against our DLLs as well as register it. After you finally did that, the solution was working, but there was another problem if you had to hotfix your project. You simply had to recompile your library to make it work. This pretty much made the ability to provide cross-version modules for our Marketplace impossible. There was one improvement in version 5.5 that handled that scenario by being able to register those items from your App_Code (), but especially with the larger libraries, it was very heavy to set that up. In fact, there was another problem that came with this solution. And that problem was in particular that different modules from the Marketplace could overwrite each others' custom code in the predefined App_Code files with their customizations. There is one last remaining thing I should cover, which was told us many times, but there was never time to make so significant changes. That issue were the custom handlers. In fact, this was caused more by historical reasons when the original version was done as a custom library mentioned above to provide enough customization options. It seemed great, because it allowed a whole new level of customization at that time, but the consequences were that it was very hard for us to update that (it simply caused the need to update your custom code), and it also couldn't use strongly typed method headers because the library was sitting too low. As you can see, there were problems with customization. Luckily, given the feature set we offer these customizations weren't needed that often, but to those who used them, it could sometimes cause headache. The good news is that Kentico CMS 6 handles all of these issues, providing much better flexibility and ease of customization! Let's see what has changed and how it effects your existing projects. Another good news is that for most of the changes, we provided backward compatibility. Kentico CMS 6 application code As I mentioned above, the Global.asax.cs file in 5.5 R2 was full of code which made it very complicated to merge it with an existing ASP.NET application that used it. What we did in version 6 is following: The code from Global.asax.cs was moved to App_Code/Application/CMSAppBase.cs, this is the basic code that executes within the request processing There is a new class CMSHttpApplication located in App_Code/Application/CMSHttpApplication.cs which connects the Global.asax.cs to the moved code Some of the event processing was moved to an HTTP module called CMSApplicationModule to provide even better options for customization. What this means at the end is pretty obvious if you look at the 6.0 Global.asax.cs. This is exactly the only thing that you need to ensure if you merge Kentico CMS with an existing ASP.NET application. One thing is to inherit the application class from CMSHttpApplication, and the other is to provide the region with the system version (this is one thing that we had to keep for backward compatibility of external tools that depend on the version). /// <summary> /// Application methods. /// </summary> public class Global : CMSHttpApplication { #region "System data (do not modify)" /// <summary> /// Application version, do not change. /// </summary> /// const stringShopping cart</param> protected override double CalculateOrderDiscountInternal(ShoppingCartInfo cart) { double result = base.CalculateOrderDiscountInternal(cart); // Example of order discount based on the time of shopping - Happy hours (4 PM - 7 PM) if ((DateTime.Now.Hour >= 16) && (DateTime.Now.Hour <= 19)) { // 20% discount result = result + cart.TotalItemsPriceInMainCurrency * 0.2; } // Example of order discount based on the total price of all cart items else if (cart.TotalItemsPriceInMainCurrency > 500) { // 10% discount result = result + cart.TotalItemsPriceInMainCurrency * 0.1; } return result; } } If you look at the provider or other providers closer, you can see a lot of overridable methods, so it is just up to you which ones you want to use. The other example with site provider just logs something to the event log when a site object is saved, but as you can see above, you can do the same through the SiteInfo.TYPEINFO.Update.After event, so it is more demonstrative than really useful. You can do the same with some helpers such as CacheHelper or MediaHelper, they have the HelperObject property to do that. Registering providers and helpers from libraries There is one more option for registering providers. You can have the provider in a compiled library and register it through your web.config. This helps to organize your project in case you have some more complex customization and have everything in one place. There is a new configuiration section that you can register within your web.config: <?xml version="1.0"?> <configuration xmlns=""> <configSections> ... <section name="cms.extensibility" type="CMS.SettingsProvider.CMSExtensibilitySection" /> </configSections> ... <cms.extensibility> <providers> <add name="SiteInfoProvider" assembly="MyLibrary" type="CustomSiteInfoProvider" /> ... </providers> <helpers> <add name="CacheHelper" assembly="MyLibrary" type="CustomCacheHelper" /> ... </helpers> </cms.extensibility> ... </configuration> This example loads the custom site provider and custom cache helper from the DLL "MyLibrary". Note that the provider and helper must inherit from the correct base system provider in order for this to work. Still, for simple scenarios, I recommend the App_Code approach with replacing the provider object programatically, it is much easier. ... well, and that is all for today, I hope you like the new ways of customizations, see some of our samples in App_Code/Samples, play around, and have a great Andrew Corkery commented on Oct 28, 2011 This is a nice improvement. I'm starting a new v6 project in a week or two, with a lot of custom requirements. This will definitely make it cleaner to separate the client-specific functionality. Cheers. Jeroen Fürst commented on Oct 25, 2011 Wow Martin, excellent post! Thanks for the detailed explanation! Martin Hejtmanek commented on Oct 24, 2011 Hi Martin,This particular method returns the discount, not the total price, so the discount really is 20% ;-)Anyway, I am glad you liked it :-) Martin commented on Oct 24, 2011 Interesting article - easy to follow and digest. We're looking forward to using version 6.0 on our next project.Btw - multiplying by 0.2 is an 80% discount ;-) New subscription Leave message Your email: | https://devnet.kentico.com/articles/code-customization-in-kentico-cms-6 | CC-MAIN-2019-43 | refinedweb | 1,304 | 54.63 |
Meet six misunderstood Ruby features
If you're a
C++ programmer and need to work in
Ruby, you have a bit of learning to do. This article discusses six Ruby
features that the Ruby newbie is likely to misunderstand, especially if he
or she comes from a similar-but-not-quite environment like
C++:
- The Ruby class hierarchy
- Singleton methods in Ruby
- The
selfkeyword
- The
method_missingmethod
- Exception handling
- Threading
Note: All code in this article was tested and based on Ruby version 1.8.7.
Class hierarchy in Ruby
Class hierarchy in Ruby can be tricky. Create a class of type
Cat and start to play with its hierarchy (see
Listing 1).
Listing 1. Implicit class hierarchy in Ruby
irb(main):092:0> class Cat irb(main):093:1> end => nil irb(main):087:0> c = Cat.new => #<Cat:0x2bacb68> irb(main):088:0> c.class => Cat irb(main):089:0> c.class.superclass => Object irb(main):090:0> c.class.superclass.superclass => nil irb(main):091:0> c.class.superclass.superclass.superclass NoMethodError: undefined method `superclass' for nil:NilClass from (irb):91 from :0
All objects in Ruby (even the user-defined objects) are descendants of the
Object class, as is obvious from Listing 1.
This is in sharp contrast to
C++. There's
nothing like a plain datatype—for example,
C/C++ int or
double.
Listing 2 shows the class hierarchy for the
integer 1.
Listing 2. Class hierarchy for 1
irb(main):100:0> 1.class => Fixnum irb(main):101:0> 1.class.superclass => Integer irb(main):102:0> 1.class.superclass.superclass => Numeric irb(main):103:0> 1.class.superclass.superclass.superclass => Object
So far so good. Now you know that classes themselves are objects of type
Class.
Class in turn
is ultimately derived from
Object, as
demonstrated in Listing 3, with the Ruby built-in
String class.
Listing 3. Class hierarchy for classes
irb(main):100:0> String.class => Class irb(main):101:0> String.class.superclass => Module irb(main):102:0> String.class.superclass.superclass => Object
Module is the base class for
Class, and it comes with the caveat that you
cannot instantiate user-defined
Module objects
directly. If you don't want to get into Ruby internals, it's safe to
consider
Module having similar characteristics
to a
C++ namespace: You can define your own
methods, constants, and so on. You include a
Module inside a
Class, and voilà, all the elements of the
Module are now magically the elements of the
Class. Listing 4 provides
an example.
Listing 4. Modules cannot be directly instantiated and can be used only with classes
irb(main):020:0> module MyModule irb(main):021:1> def hello irb(main):022:2> puts "Hello World" irb(main):023:2> end irb(main):024:1> end irb(main):025:0> test = MyModule.new NoMethodError: undefined method `new' for MyModule:Module from (irb):25 irb(main):026:0> class MyClass irb(main):027:1> include MyModule irb(main):028:1> end => MyClass irb(main):029:0> test = MyClass.new => #<MyClass:0x2c18bc8> irb(main):030:0> test.hello Hello World => nil
Here's the recap, then: When you write
c = Cat.new in Ruby,
c is an object of type
Cat that is derived from
Object. The
Cat
class is an object of type
Class, which is
derived from
Module, which is in turn derived
from
Object. Both the object and its type are
thus valid Ruby objects.
Singleton methods and editable classes
Now, look at singleton methods. Suppose you want to model something
akin to the human society in
C++. How would you
do it? Have a class called
Human, and then have
millions of
Human objects? That's more like
modeling a zombie society; each human must have some unique
characteristic. Ruby's singleton methods come in handy here, as explained
in Listing 5.
Listing 5. Singleton methods in Ruby
irb(main):113:0> y = Human.new => #<Human:0x319b6f0> irb(main):114:0> def y.paint irb(main):115:1> puts "Can paint" irb(main):116:1> end => nil irb(main):117:0> y.paint Can paint => nil irb(main):118:0> z = Human.new => #<Human:0x3153fc0> irb(main):119:0> z.paint NoMethodError: undefined method `paint' for #<Human:0x3153fc0> from (irb):119
Singleton methods in Ruby are methods only associated with a
particular object and not available to the general class. They are
prefixed with the object name. In Listing 5, the
paint method is specific to the object
y and
y alone;
z.paint results in an undefined method error.
You can figure out the list of singleton methods in an object by calling
singleton_methods:
irb(main):120:0> y.singleton_methods => ["paint"]
There's yet another way of defining singleton methods in Ruby. Consider the code in Listing 6.
Listing 6. Yet another way of creating singleton methods
irb(main):113:0> y = Human.new => #<Human:0x319b6f0> irb(main):114:0> class << y irb(main):115:1> def sing irb(main):116:1> puts "Can sing" irb(main):117:1> end irb(main):118:1>end => nil irb(main):117:0> y.sing Can sing => nil
Listing 5 also opens interesting possibilities about adding new methods to
user-defined classes and to built-in Ruby existing classes
like
String. That's impossible in
C++ unless you have access to the source code
for the classes that you use. Look into the
String class once more (Listing 7).
Listing 7. Ruby allows you to modify an existing class
irb(main):035:0> y = String.new("racecar") => "racecar" irb(main):036:0> y.methods.grep(/palindrome/) => [ ] irb(main):037:0> class String irb(main):038:1> def palindrome? irb(main):039:2> self == self.reverse irb(main):040:2> end irb(main):041:1> end irb(main):050:0> y.palindrome? => true
Listing 7 clearly illustrates how you can edit an existing Ruby class to
add the methods of your choice. Here, I added the
palindrome? method to the
String class. Ruby classes are therefore
editable at run time—a powerful property.
Now that you have some idea of Ruby's class hierarchy and singletons, let's
move on to the
self. Note that I used
self while defining the
palindrome? method.
Discovering self
The most common use of the
self keyword is
perhaps to declare a static method in a Ruby class, as in Listing 8.
Listing 8. Using self to declare class static methods
class SelfTest def self.test puts "Hello World with self!" end end class SelfTest2 def test puts "This is not a class static method" end end SelfTest.test SelfTest2.test
As you can see in the output from Listing 8—shown in Listing 9—you cannot invoke non-static
methods without objects. The behavior resembles
C++.
Listing 9. Error when non-static methods are called without objects
irb(main):087:0> SelfTest.test Hello World with self! => nil irb(main):088:0> SelfTest2.test NoMethodError: undefined method 'test' for SelfTest2:Class from (irb):88
Before moving on to more esoteric uses and meanings of
self, note that you can also define a static
method in Ruby by prefixing the class name before the method name:
class TestMe def TestMe.test puts "Yet another static member function" end end TestMe.test # works fine
Listing 10 offers a more interesting but rather
difficult-looking use of
self.
Listing 10. Using meta-class to declare static methods
class MyTest class << self def test puts "This is a class static method" end end end MyTest.test # works fine
This code defines
test as a class static method
in a slightly different way. To understand what's happening, you need to
look at the
class << self syntax in some
detail.
class << self … end creates a
meta-class. In the method lookup chain, the meta-class of an object is searched
before accessing the base class of the object. If you define a method in the
meta-class, it can be invoked on the class. This is similar to the notion
of static methods in
C++.
Is it possible to access a meta-class? Yes: Just return
self from inside
class << self … end. Note that in a Ruby
class declaration, you are under no obligation to put only method
definitions. Listing 11 shows the meta-class.
Listing 11. Getting hold of the meta-class
irb(main):198:0> class MyTest irb(main):199:1> end => nil irb(main):200:0> y = MyTest.new => #< MyTest:0x2d43fe0> irb(main):201:0> z = class MyTest irb(main):202:1> class << self irb(main):203:2> self irb(main):204:2> end irb(main):205:1> end => #<Class: MyTest > irb(main):206:0> z.class => Class irb(main):207:0> y.class => MyTest
Coming back to the code in Listing 7, you see that
palindrome is defined as
self == self.reverse. In this context,
self is no different from
C++. The methods in
C++ and likewise in Ruby need an object to act
upon to modify or extract state information.
self refers to that object here. Note that
public methods can optionally be called by prefixing the
self keyword to indicate the object on which
the method is acting, as in Listing 12.
Listing 12. Using self to invoke methods
irb(main):094:0> class SelfTest3 irb(main):095:1> def foo irb(main):096:2> self.bar() irb(main):097:2> end irb(main):098:1> def bar irb(main):099:2> puts "Testing Self" irb(main):100:2> end irb(main):101:1> end => nil irb(main):102:0> test = SelfTest3.new => #<SelfTest3:0x2d15750> irb(main):103:0> test.foo Testing Self => nil
You cannot call private methods in Ruby with the
self keyword prefixed. For a
C++ developer, this might get pretty
confusing. The code in Listing 13 clearly shows that
self cannot be used with private methods: The
call to the private method must only be made with an implicit object.
Listing 13. self cannot be used with private method invocation
irb(main):110:0> class SelfTest4 irb(main):111:1> def method1 irb(main):112:2> self.method2 irb(main):113:2> end irb(main):114:1> def method3 irb(main):115:2> method2 irb(main):116:2> end irb(main):117:1> private irb(main):118:1> def method2 irb(main):119:2> puts "Inside private method" irb(main):120:2> end irb(main):121:1> end => nil irb(main):122:0> y = SelfTest4.new => #<SelfTest4:0x2c13d80> irb(main):123:0> y.method1 NoMethodError: private method `method2' called for #<SelfTest4:0x2c13d80> from (irb):112:in `method1' irb(main):124:0> y.method3 Inside private method => nil
Because everything in Ruby is an object, here's what you get when you
invoke
self on the
irb prompt:
irb(main):104:0> self => main irb(main):105:0> self.class => Object
The moment you launch
irb, the Ruby interpreter
creates the main object for you. This main object is also known as the
top-level context in the Ruby-related literature.
Enough of
self. Let's move on to dynamic methods and the
method_missing method.
The mystery behind method_missing
Consider the Ruby code in Listing 14.
Listing 14. method_missing in action
irb(main):135:0> class Test irb(main):136:1> def method_missing(method, *args) irb(main):137:2> puts "Method: #{method} Args: (#{args.join(', ')})" irb(main):138:2> end irb(main):139:1> end => nil irb(main):140:0> t = Test.new => #<Test:0x2c7b850> irb(main):141:0> t.f(23) Method: f Args: (23) => nil
Clearly, if voodoo is your thing, Listing 14 should bring smile to your
face. What happened here? You created an object of type
Test, and then called
t.f with
23 as an
argument. But
Test did not have
f as a method, and you should get a
NoMethodError or similar error message. Ruby is
doing something fascinating here: Your method calls are being intercepted
and handled by
method_missing. The first
argument to
method_missing is the method name
that's missing—in this case,
f. The
second and last argument is
*args, which
captures the arguments being passed to
f. Where
could you use something like this? Among other options, you could easily
forward method calls to an included
Module or a
component object without explicitly providing a wrapper application
programming interface for each call in the top-level class.
Take a look at some more voodoo in Listing 15.
Listing 15. Using the send method to pass arguments to a routine
irb(main):142:0> class Test irb(main):143:1> def method1(s, y) irb(main):144:2> puts "S: #{s} Y: #{y}" irb(main):145:2> end irb(main):146:1> end => nil irb(main):147:0>t = Test.new irb(main):148:0> t.send(:method1, 23, 12) S: 23 Y: 12 => nil
In Listing 15,
class Test has a method
called
method1 defined. However, instead of
calling the method directly, you make a call to the
send method.
send is
a public method of the class
Object and
therefore available for
Test (all classes are
derived from
Object, remember). The first
argument to the
send method is a symbol or
string that denotes the method name. What can the
send method do that in the normal course you
cannot? You can access private methods of a class using the
send method. Of course, whether this is a good
feature to have remains debatable. Look at the code in Listing 16.
Listing 16. Accessing class private methods
irb(main):258:0> class SendTest irb(main):259:1> private irb(main):260:1> def hello irb(main):261:2> puts "Saying Hello privately" irb(main):262:2> end irb(main):263:1> end => nil irb(main):264:0> y = SendTest.new => #< SendTest:0x2cc52c0> irb(main):265:0> y.hello NoMethodError: private method `hello' called for #< SendTest:0x2cc52c0> from (irb):265 irb(main):266:0> y.send(:hello) Saying Hello privately => nil
Throw and catch are not what they seem
If you come from a
C++ background like I do and
have a tendency to try writing exception-safe code, then you will
probably start feeling at home the moment you see that Ruby has the
throw and
catch
keywords. Unfortunately,
throw and
catch have a completely different meaning in
Ruby.
Ruby typically handles exceptions using
begin…rescue blocks. Listing 17 provides an example.
Listing 17. Exception handling in Ruby
begin f = File.open("ruby.txt") # .. continue file processing rescue ex => Exception # .. handle errors, if any ensure f.close unless f.nil? # always execute the code in ensure block end
In Listing 17, if something bad happens while trying to open the file
(maybe a missing file or an issue with file permissions), the code in the
rescue block runs. The code in the
ensure block always runs, irrespective
of whether any exceptions were raised. Note that the presence of the
ensure block after the
rescue block is optional, however. Also, if an
exception must be thrown explicitly, then the syntax is
raise <MyException>. If you choose to
have your own exception class, you might want to derive the same from
Ruby's built-in
Exception class to take
advantage of existing methods.
The catch-and-throw facility in Ruby is not really exception handling: You
can use
throw to alter program flow. Listing 18 shows an example using
throw and
catch.
Listing 18. Throw and catch in Ruby
irb(main):185:0> catch :label do irb(main):186:1* puts "This will print" irb(main):187:1> throw :label irb(main):188:1> puts "This will not print" irb(main):189:1> end This will print => nil
In Listing 18, when the code flow hits the
throw
statement, the execution is interrupted, and the interpreter begins
looking for a
catch block that handles the
corresponding symbol. Execution is restarted from where the
catch block ends. Look at the example of
throw and
catch in
Listing 19: Note that you can easily spread
catch and
throw
statements across functions.
Listing 19. Exception handling in Ruby: nested catch blocks
irb(main):190:0> catch :label do irb(main):191:1* catch :label1 do irb(main):192:2* puts "This will print" irb(main):193:2> throw :label irb(main):194:2> puts "This won't print" irb(main):195:2> end irb(main):196:1> puts "Neither will this print" irb(main):197:1> end This will print => nil
Some people have gone to the extent of saying that Ruby takes the
C
goto madness to altogether new heights
with its
catch and
throw support. Given that there could be
several nested layers of functions with
catch
blocks possible at every level, the
goto
madness analogy does seem to have some steam here.
Threads in Ruby can be green
Ruby version 1.8.7 does not support true
concurrency. It really, truly does not. But you have the Thread construct
in Ruby, you say. Right you are. But that
Thread.new does not spawn a real operating
system thread every time you make a call to the same. What Ruby supports
is green threads: The Ruby interpreter uses a single operating
system thread to handle the workload from multiple application-level
threads.
This "green thread" concept is useful while some thread is waiting on some I/O to occur, and you can easily schedule a different Ruby thread to make good use of the CPU. But this construct cannot use a modern multi-core CPU. (Wikipedia provides an excellent piece that explains what green threads are. See Related topics for a link.)
This final example (see Listing 20) proves the point.
Listing 20. Multiple threads in Ruby
#!/usr/bin/env ruby def func(id, count) i = 0; while (i < count) puts "Thread #{i} Time: #{Time.now}" sleep(1) i = i + 1 end end puts "Started at #{Time.now}" thread1 = Thread.new{func(1, 100)} thread2 = Thread.new{func(2, 100)} thread3 = Thread.new{func(3, 100)} thread4 = Thread.new{func(4, 100)} thread1.join thread2.join thread3.join thread4.join puts "Ending at #{Time.now}"
Assuming that you have the
top utility on your
Linux® or UNIX® box, run the code in a terminal, get the process
ID, and run
top –p <process id>. When
top starts, press Shift-H to list the number of
threads running. You should see only a single thread confirming what you
knew anyway: concurrency in Ruby 1.8.7 is a myth.
All that said, green threads are not bad. They are still useful in heavy-duty I/O-bound programs, not to mention that this approach is probably the most portable across operating systems.
Conclusion
This article covered quite a few areas:
- Notions of class hierarchy in Rub
- nSingleton methods
- Deciphering the
selfkeyword and
method_missingmethod
- Exceptions
- Threading
Notwithstanding its quirks, Ruby is fun to program in and extremely powerful in its ability to do a lot with minimum code. No wonder, then, that large-scale applications like Twitter are using Ruby to harness their true potential. Happy coding in Ruby!
Downloadable resources
Related topics
- Read Programming Ruby: The Pragmatic Programmers' Guide (Dave Thomas, Chad Fowler, and Andy Hunt; 2nd edition), a Ruby must-read that is popularly known as the Pickaxe book.
- Check out another invaluable Ruby resource, The Ruby Programming Language [Yukihiro "Matz" Matsumoto (Ruby's creator) and David Flanagan, O'Reilly, 2008].
- Visit To Ruby From C and C++, a great site for
C/C++programmers who want to learn Ruby.
- Learn more about green threads in a good explanation on Wikipedia.
- In the developerWorks Linux zone, find hundreds of how-to articles and tutorials, as well as downloads, discussion forums, and a wealth of other resources for Linux developers and administrators.
- Follow developerWorks on Twitter. | http://www.ibm.com/developerworks/opensource/library/os-sixrubyfeatures/index.html?ca=drs- | CC-MAIN-2017-13 | refinedweb | 3,305 | 66.03 |
,
- Fixed.
Hi:I want to instantiate a list template like the following:
%include <std_list.i>
%template(margList) std::list<Sequence::marginal>;#marginal is a class
defined in Sequence namespace
when I complie, the error appeared :
*/usr/include/c++/4.0.0/bits/stl_list.h:482: error: no matching function for
call to ‘Sequence::marginal::marginal()’*
I searched on line and found a solution:
%ignore std::list<maginal>::list(size_type);
%include <std_list.i>
%template(margList) std::list<Sequence::marginal>;
But the same error reemerged!
PS: For the other classes defined in Sequence namespace, no error!
Does anyone can give me some suggestion? Thanks.
--
Xin Shuai (David)
PhD of Complex System in School of Informatics
Indiana University Bloomington
812-606-8019
Hi William,
>>>>> "WSF" == William S Fulton <William> writes:
WSF> When you say you want to associate Perl code with a type, do you mean
WSF> just class or any type, such as a struct/union/class/primitive type, as
WSF> well as pointers/reference pointer references etc etc?
A class was my intent, but for a more general solution, one would
probably want to consider any/every type.
WSF> Assuming yes, there is no such type node that I can think
WSF> of. Features don't attach to types, they attach to
WSF> functions/methods and classes/structs/unions and enums, so you
WSF> can't use a feature.
Well... I did use a feature, actually, and it seems to work without a
hitch, at least for what I needed. I did have to do a bit of a
brute-force walk of the parse tree in order to find the feature data,
but this seems to work.
(I was quite tempted, as I was doing this, to simply import the data I
needed into swig without involving the .i files, the parse tree and
DOH. Walking the parse tree is not nearly as simple as I'd like, and
DOH ... well ... let's just say that I'm not a fan of DOH. I thought
about adding support for sqlite [] but I simply
hate messing with autoconf, so I opted to not do that. But, had
sqlite been available, the choice of using sqlite over DOH would have
been a no-brainer.)
WSF> Of course typemaps are associated with types and you are probably
WSF> looking at inventing a new typemap. This is usually to be
WSF> avoided, so I think it would be best to give an detailed example
WSF> of what you are trying to do.
Agreed: I really don't want another typemap. Certainly not a static
typemap. A feature is kinda, sorta less than a typemap, at least in
my brain, and it was sufficient for what I needed. Since swig already
supports them, that's what I chose to use.
Ok, here's a description of what I've got and what I'm trying to
achieve:
- We use SWIG for our system. We support perl, tcl and
python, and all are simultaneously active.
- For our system, we have a class called bomValue. bomValue
objects are basically a discriminated union. Eg, there's a
type indicator and a union of bool, ints of various flavors,
floats of various flavors, a string and a pointer. Think of
this as how you'd implement a perl (or python or tcl or ...)
variable and you'd not be too far off. This sort of thing
is also commonly used for yacc parsers.
- The bomValue class is not exposed to the extension
languages. Instead, the data within a bomValue object is
unpacked and exported into the extension language (or vice
versa). We have typemaps that deal with the un/packing of a
bomValue object, and the conversion goes in both directions.
- The issue I was trying to solve is, what's the best way to
deal with the pointer when sending this to perl. I need to
convert this into a blessed reference on the perl side, but
this happens selectively because the bomValue may store an
int or float or ... We also take the pointer's type into
account so that we can dynamically determine the package to
use when blessing the pointer/ref.
- Before, we had a "trampoline" function that handled all of
this, but it turns out that this wasn't reliable (owing to
quirks in perl) and we had a couple of significant memory
leaks.
- The change I made has eliminated these leaks. It works by
avoiding the trampoline function and handling the pointer
directly, with some help from the perl code that is
expressed with the feature directive.
Given what our typemap does in C++ land, the perl code expressed
within the feature is pretty simple:
#if defined(SWIGPERL)
%feature("perlafter") bomValue
%{
return undef if (!defined($result));
return $result if (! ref($result));
my %resulthash;
tie %resulthash, ref($result), $result;
return bless \%resulthash, ref($result);
%}
#endif
Yes, this looks like what swig already generates, except that this is
for a type that isn't directly exposed to the extension languages.
The modified perl5.cxx code that handles this feature is shown below.
This is for the functionWrapper() function; similar modifications were
made to the memberfunctionHandler() function.
Note: we're using an older version of SWIG (a '36 vintage) so this
won't match up with the latest '40 version you've got.
...
if (blessed &&
!member_func)
{
bool bWroteInterestingStubCode = false;
String *func = NewString("");
//-------------------------------------------------------
// We'll make a stub since we may need it anyways
//-------------------------------------------------------
Printv(func, "sub ", iname, " {\n",
tab4, "my @args = @_;\n",
NIL);
//-------------------------------------------------------
// Get user-supplied 'before' code, if any.
//-------------------------------------------------------
String* pBeforeCode = 0;
String* pAfterCode = 0;
GetBeforeAfterText(pReturnType, pBeforeCode, pAfterCode);
if (pBeforeCode != 0)
{
Printf(func, "%s", pBeforeCode);
bWroteInterestingStubCode = true;
}
//-------------------------------------------------------
// Call the internal function.
//-------------------------------------------------------
Printv(func, tab4, "my $result = ", cmodule, "::", iname, "(@args);\n", NIL);
//-------------------------------------------------------
// Get user-supplied 'after' code, if any. If there
// is 'after' code, this is all that will be written.
//-------------------------------------------------------
if (pAfterCode != 0)
{
Printf(func, "%s}\n", pAfterCode);
bWroteInterestingStubCode = true;
}
...
Yes, I've completely ignored the indentation and commenting style used
in the rest of swig. I wasn't planning on releasing this in the wild
so, please, no flames.
In order to get this to work, I needed some extra code to find the
feature data in the parse tree. Quite a bit of extra code, actually.
I've included this code at the end of the file. This is a brute-force
search and not very elegant. Perhaps there are better ways to search
the parse tree in swig, and I'd be happy to have a tutorial on this.
(Id' be far happier if I could get the parse tree shoved into a sqlite
database. Then searching would be much simpler.)
WSF> Incidentally, I don't know of any scripting language typemaps
WSF> that generate scripting language code, they are used for c/c++
WSF> code, but perhaps someone else knows of some. Java and C#, on the
WSF> other hand generate all the Java/C# code using typemaps, and they
WSF> take quite a different approach to this part of the code
WSF> generation. I'd suggest that if typemaps are to start generating
WSF> Perl code, that they go the whole way like Java/C#.
Well, I've said this for years: instead of implementing yet another
static typemap, I'd be inclined to make the system support 'active'
functions instead. That is, I'd be pleased (read: thrilled) if I
could register a function with the system and then have swig invoke
that function at certain points as the parse tree is scanned. A
function is much preferred over static text in a typemap.
Thanks for your help. If you see flaws in the code I'd like to hear
about them.
--
David Fletcher Tuscany Design Automation, Inc.
david.fletcher@... 3030 S. College Ave.
Ft. Collins, CO 80525 USA
PS If you ever want to explore adding sqlite to swig, I'd be eager to
discuss this and quite willing to help.
- sqlite is public domain, so licensing shouldn't be an issue.
- The quality of the code is quite high, with testing that
results in well over 95% branch coverage.
- There is an active community for this DB, and it has been
ported to a wide variety of systems. Linux, Mac, Windows,
iPhone, etc. It's part of Firefox. Etc, etc.
- There are interfaces to sqlite from all of the major
extension languages (perl, tcl, python, lua, ...).
- There are only 3 files --- two header files and one C file
--- that need to be added to the mix within Swig.
- sqlite is written in C. I'd be happy to help develop a C++
interface for use within SWIG.
I believe that the use of sqlite would make certain oeprations
substantially easier. Eg, the brute-force code below, could be
achieved in a dozen lines of code. Probably less.
Here's the brute-force scan of the parse tree:
/*----------------------------------------------------------------------------
* static bool
* GetBeforeAfterTextHelper(...)
*
*//*!
*
* Given a node, find a child named "include", or one named 'classforward'.
* The 'classforward' nodes are the ones we're after, but only if this node
* matches the name of the desired type, and if there are 'perlbefore' and/or
* 'perlafter' key attributes on the 'classforward' node.
*
*//*-----------------------------------------------------------------------*/
static bool
GetBeforeAfterTextHelper(String* pDesiredTypeName,
Node* pOrigNode,
String*& rpBeforeCode,
String*& rpAfterCode,
int iLevel)
{
//-------------------------------------------------------
// Given a node, examine this node and all of its siblings.
// In other words, examine one level of a tree.
//-------------------------------------------------------
for (Node* pNode = pOrigNode; pNode != 0; pNode = nextSibling(pNode))
{
//-------------------------------------------------------
// Get the 'nodeType' for the node. We want this to
// match 'include' or 'classforward'.
//
// We'll handle the 'include' case first. Basically,
// all we do is examine the immediate children of these
// nodes.
//-------------------------------------------------------
String* pNodeType = nodeType(pNode);
if (pNodeType == 0)
continue;
if (Cmp(pNodeType, "include") == 0)
{
bool bResult = GetBeforeAfterTextHelper(pDesiredTypeName,
firstChild(pNode),
rpBeforeCode,
rpAfterCode,
iLevel + 1);
if (bResult == true)
return true;
}
//-------------------------------------------------------
// The next case we need to consider is the 'classforward'
// node. We'll find the 'sym:name' attribute on this
// node and this should, hopefully, match the name of the
// desired type.
//-------------------------------------------------------
if (Cmp(pNodeType, "classforward") != 0)
continue;
String* pSymName = Getattr(pNode, "sym:name");
if (pSymName == 0)
continue;
if (Cmp(pSymName, pDesiredTypeName) != 0)
continue;
//-------------------------------------------------------
// Ok, we found a candidate node. Now, we need to see
// if we can find the 'perlbefore' and/or 'perlafter'
// attributes... except these are key attributes. What's
// the difference? Who knows? I don't. Anyway, we're
// looking for perlbefore/perlafter and, should we be
// fortunate enough to find these, we're done.
//-------------------------------------------------------
String* pKey;
for (Iterator ki = First(pNode);
(pKey = ki.key) != 0;
ki = Next(ki))
{
if (! DohIsString(Getattr(pNode, pKey)))
continue;
//-------------------------------------------------------
// Before...
//-------------------------------------------------------
if (rpBeforeCode == 0)
{
if (Cmp(pKey, "feature:perlbefore") == 0)
{
rpBeforeCode = Getattr(pNode, pKey);
continue;
}
}
//-------------------------------------------------------
// After...
//-------------------------------------------------------
if (rpAfterCode == 0)
{
if (Cmp(pKey, "feature:perlafter") == 0)
{
rpAfterCode = Getattr(pNode, pKey);
continue;
}
}
//-------------------------------------------------------
// Success? If we happened to find both the 'before'
// and 'after' values, we're done. Otherwise, we'll
// keep scanning until we have both (and the first
// definition wins, by the way).
//-------------------------------------------------------
if (rpBeforeCode != 0 ||
rpAfterCode != 0)
return true;
}
}
//-------------------------------------------------------
// If, after the scan, we have EITHER the 'before' or
// 'after', we'll call this a success. Otherwise, we'll
// return false to indicate that we couldn't find this
// information.
//-------------------------------------------------------
if (rpBeforeCode != 0 ||
rpAfterCode != 0)
return true;
return false;
}
/*----------------------------------------------------------------------------
* static bool
* GetBeforeAfterText(SwigType* pType, String*& rpBeforeCode, String*& rpAfterCode)
*
*//*!
*
* Now, I will admit that there may be a better way to go about all of
* this, because this function is searching what I'm presuming to be the
* raw parse tree. I would guess that there's a "compiled" form of this
* tree .... but since I don't see anything like this....
*
* What we have to do is navigate from a "desired" type, which is probably
* the return type for some function. Then, we jump through some hoops
* to get the name of the type in a form we can use. Then, we'll do a
* semi-brute-force scan of the raw parse tree to find the information
* we're after.
*
*//*-----------------------------------------------------------------------*/
static bool
GetBeforeAfterText(SwigType* pDesiredType,
String*& rpBeforeCode,
String*& rpAfterCode)
{
//-------------------------------------------------------
// Initialize rpBeforeCode and rpAfterCode. These
// will hold the strings of perl code we'd like to insert
// into the output.
//-------------------------------------------------------
rpBeforeCode = 0;
rpAfterCode = 0;
if (pDesiredType == 0)
return false;
//-------------------------------------------------------
// Given the desired type, find the node that represents
// this type. If we can't find this, there's a problem,
// so return right away.
//-------------------------------------------------------
Node* pDesiredTypeNode = Swig_symbol_clookup(pDesiredType, 0);
if (pDesiredTypeNode == 0)
return false;
//-------------------------------------------------------
// Now, we need the string equivalent for this Node.
// sym:name is probably what we're after, as this should
// be the simple, unadorned type name. But, we'll extend
// the search just a bit in order to cover all of the bases.
//-------------------------------------------------------
String* pDesiredTypeNodeName = Getattr(pDesiredTypeNode, "sym:name");
if (pDesiredTypeNodeName == 0)
pDesiredTypeNodeName = Getattr(pDesiredTypeNode, "name");
if (pDesiredTypeNodeName == 0)
pDesiredTypeNodeName = nodeType(pDesiredTypeNode);
if (pDesiredTypeNodeName == 0)
{
Printf(stdout, "-E- Could not find pDesiredTypeNodeName\n");
return false;
}
//-------------------------------------------------------
// First, we'll walk up from the node to the top of
// the tree. Then, we'll examine the top node's immediate
// children.
//-------------------------------------------------------
Node* pTop = pDesiredTypeNode;
while (1)
{
Node* pParent = parentNode(pTop);
if (pParent == 0)
break;
pTop = pParent;
}
//-------------------------------------------------------
// Now, we'll need to find the node in the raw parse
// tree that matches this type name. We'll do this by
// walking down a level or two to look for this node
// that happens to have the perlbefore and/or perlafter
// attributes.
//-------------------------------------------------------
bool bResult = GetBeforeAfterTextHelper(pDesiredTypeNodeName,
firstChild(pTop),
rpBeforeCode,
rpAfterCode, 1);
return bResult;
}
I agree to receive quotes, newsletters and other information from sourceforge.net and its partners regarding IT services and products. I understand that I can withdraw my consent at any time. Please refer to our Privacy Policy or Contact Us for more details | https://sourceforge.net/p/swig/mailman/swig-devel/?viewmonth=200907&viewday=19 | CC-MAIN-2017-22 | refinedweb | 2,279 | 64 |
Hacking Super Mario Bros. with Python
This weekend I was coming home from the meeting of the LSST Dark Energy Science Collaboration, and found myself with a few extra hours in the airport. I started passing the time by poking around on the imgur gallery, and saw a couple animated gifs based on one of my all-time favorite games, Super Mario Bros. It got me wondering: could I use matplotlib's animation tools to create these sorts of gifs in Python? Over a few beers at an SFO bar, I started to try to figure it out. To spoil the punchline a bit, I managed to do it, and the result looks like this:
This animation was created entirely in Python and matplotlib, by scraping the image data directly from the Super Mario Bros. ROM. Below I'll explain how I managed to do it.
Scraping the Pixel Data
Clearly, the first requirement for this pursuit is to get the pixel data used to construct the mario graphics. My first thought was to do something sophisticated like dictionary learning on a collection of screen-shots from the game to build up a library of thumbnails. That would be an interesting pursuit in itself, but it turns out it's much more straightforward to directly scrape the graphics from the source.
It's possible to find digital copies of most Nintendo Entertainment System (NES) games online. These are known as ROMs, and can be played using one of several NES emulators available for various operating systems. I'm not sure about the legality of these digital game copies, so I won't provide a link to them here. But the internet being what it is, you can search Google for some variation of "Super Mario ROM" and pretty easily find a copy to download.
One interesting aspect of ROMs for the original NES is that they use raw byte-strings to store 2-bit (i.e. 4-color), 8x8 thumbnails from which all of the game's graphics are built. The collection of these byte-strings are known as the "pattern table" for the game, and there is generally a separate pattern table for foreground and background images. In the case of NES games, there are 256 foreground and 256 background tiles, which can be extracted directly from the ROMs if you know where to look (incidentally, this is one of the things that made the NES an "8-bit" system. 2^8 = 256, so eight bits are required to specify any single tile from the table).
Extracting Raw Bits from a File
If you're able to obtain a copy of the ROM, the first step to getting at the
graphics is to extract the raw bit information.
This can be done easily in Python using
numpy.unpackbits
and
numpy.frombuffer or
numpy.fromfile.
Additionally, the ROMs are generally stored using
zip compression. The uncompressed data can be extracted using Python's
built-in
zipfile module. Combining all of this, we extract the raw file
bits using a function like the following:
import zipfile import numpy as np def extract_bits(filename): if zipfile.is_zipfile(filename): zp = zipfile.ZipFile(filename) raw_buffer = zp.read(zp.filelist[0]) bytes = np.frombuffer(raw_buffer, dtype=np.uint8) else: bytes = np.fromfile(filename, dtype=np.uint8) return np.unpackbits(bytes)
This function checks whether the file is compressed using zip, and extracts the raw bit information in the appropriate way.
Assembling the Pattern Tables
The thumbnails which contain the game's graphics patterns are not at any set location within the file. The location is specified within the assembly code that comprises the program, but for our purposes it's much simpler to just visualize the data and find it by-eye. To accomplish this, I wrote a Python script (download it here) based on the above data extraction code which uses matplotlib to interactively display the contents of the file. Each thumbnail is composed from 128 bits: two 64-bit chunks each representing an 8x8 image with one bit per pixel. Stacking the two results in two bits per pixel, which are able to represent four colors within each thumbnail. The first few hundred chunks are difficult to interpret by-eye. They appear similar to a 2D bar code: in this case the "bar code" represents pieces of the assembly code which store the Super Mario Bros. program.
Scrolling down toward the end of the file, however, we can quickly recognize the thumbnails which make up the game's graphics:
This first pattern table contains all the foreground graphics for the game. Looking closely, the first few thumbnails are clearly recognizable as pieces of Mario's head and body. Going on we see pieces of various enemies in the game, as well as the iconic mushrooms and fire-flowers.
The second pattern table contains all the background graphics for the game. Along with numbers and text, this contains the pieces which make up mario's world: bricks, blocks, clouds, bushes, and coins. Though all of the above tiles are shown in grayscale, we can add color by simply changing the matplotlib Colormap, as we'll see below.
Combining Thumbnails and Adding Color
Examining the pattern tables above, we can see that big Mario is made up of eight pattern tiles stitched together, while small Mario is made up of four. With a bit of trial and error, we can create each of the full frames and add color to make them look more authentic. Below are all of the frames used to animate Mario's motion throughout the game:
Similarly, we can use the thumbnails to construct some of the other familiar graphics from the game, including the goombas, koopa troopas, beetle baileys, mushrooms, fire flowers, and more.
The Python code to extract, assemble, and plot these images can be downloaded here.
Animating Mario
With all of this in place, creating an animation of Mario is relatively easy. Using matplotlib's animation tools (described in a previous post), all it takes is to decide on the content of each frame, and stitch the frames together using matplotlib's animation toolkit. Putting together big Mario with some scenery and a few of his friends, we can create a cleanly looping animated gif.
The code used to generate this animation is shown below. We use the same
NESGraphics class used to draw the frames above, and stitch them together
with a custom class that streamlines the building-up of the frames.
By uncommenting the line near the bottom, the result will be saved as an
animated GIF using the ImageMagick animation writer that I
recently contributed
to matplotlib. The ImageMatick plugin has not yet made it into a
released matplotlib version, so using the save command below will
require installing the development version of matplotlib, available for
download on github.
"""Extract and draw graphics from Mario By Jake Vanderplas, 2013 <> License: GPL. Feel free to use and distribute, but keep this attribution intact. """ from collections import defaultdict import zipfile import numpy as np from matplotlib import pyplot as plt from matplotlib.colors import ListedColormap from matplotlib import animation class NESGraphics(object): """Class interface for stripping graphics from an NES ROM""" def __init__(self, filename='mario_ROM.zip', offset=2049): self.offset = offset if zipfile.is_zipfile(filename): zp = zipfile.ZipFile(filename) data = np.unpackbits(np.frombuffer(zp.read(zp.filelist[0]), dtype=np.uint8)) else: data = np.unpackbits(np.fromfile(filename, dtype=np.uint8)) self.data = data.reshape((-1, 8, 8)) def generate_image(self, A, C=None, transparent=False): """Generate an image from the pattern table. Parameters ---------- A : array_like an array of integers indexing the thumbnails to use. The upper-left corner of the image is A[0, 0], and the bottom-right corner is A[-1, -1]. A negative index indicates that the thumbnail should be flipped horizontally. C : array-like The color table for A. C should have shape A.shape + (4,). C[i, j] gives the values associated with the four bits of A for the output image. transparent : array_like if true, then zero-values in A will be masked for transparency Returns ------- im : ndarray or masked array the image encoded by A and C """ A = np.asarray(A) if C is None: C = range(4) # broadcast C to the shape of A C = np.asarray(C) + np.zeros(A.shape + (1,)) im = np.zeros((8 * A.shape[0], 8 * A.shape[1])) for i in range(A.shape[0]): for j in range(A.shape[1]): # extract bits ind = 2 * (abs(A[i, j]) + self.offset) thumb = self.data[ind] + 2 * self.data[ind + 1] # set bit colors thumb = C[i, j, thumb] # flip image if negative if A[i, j] < 0: thumb = thumb[:, ::-1] im[8 * i:8 * (i + 1), 8 * j:8 * (j + 1)] = thumb if transparent: im = np.ma.masked_equal(im, 0) return im class NESAnimator(): """Class for animating NES graphics""" def __init__(self, framesize, figsize=(8, 6), filename='mario_ROM.zip', offset=2049): self.NG = NESGraphics() self.figsize = figsize self.framesize = framesize self.frames = defaultdict(lambda: []) self.ims = {} def add_frame(self, key, A, C=None, ctable=None, offset=(0, 0), transparent=True): """add a frame to the animation. A & C are passed to NESGraphics.generate_image""" cmap = ListedColormap(ctable) im = self.NG.generate_image(A, C, transparent=transparent) self.frames[key].append((im, cmap, offset)) def _initialize(self): """initialize animation""" A = np.ma.masked_equal(np.zeros((2, 2)), 0) for i, key in enumerate(sorted(self.frames.keys())): self.ims[key] = self.ax.imshow(A, interpolation='nearest', zorder=i + 1) self.ax.set_xlim(0, self.framesize[1]) self.ax.set_ylim(0, self.framesize[0]) return tuple(self.ims[key] for key in sorted(self.ims.keys())) def _animate(self, i): """animation step""" for key in sorted(self.frames.keys()): im, cmap, offset = self.frames[key][i % len(self.frames[key])] self.ims[key].set_data(im) self.ims[key].set_cmap(cmap) self.ims[key].set_clim(0, len(cmap.colors) - 1) self.ims[key].set_extent((offset[1], im.shape[1] / 8 + offset[1], offset[0], im.shape[0] / 8 + offset[0])) return tuple(self.ims[key] for key in sorted(self.ims.keys())) def animate(self, interval, frames, blit=True): """animate the frames""" self.fig = plt.figure(figsize=self.figsize) self.ax = self.fig.add_axes([0, 0, 1, 1], frameon=False, xticks=[], yticks=[]) self.ax.xaxis.set_major_formatter(plt.NullFormatter()) self.ax.yaxis.set_major_formatter(plt.NullFormatter()) self.anim = animation.FuncAnimation(self.fig, self._animate, init_func=self._initialize, frames=frames, interval=interval, blit=blit) self.fig.anim = self.anim return self.anim def animate_mario(): NA = NESAnimator(framesize=(12, 16), figsize=(4, 3)) # Set up the background frames bg = np.zeros((12, 18), dtype=int) bg_colors = np.arange(4) + np.zeros((12, 18, 4)) bg_ctable = ['#88AACC', 'tan', 'brown', 'black', 'green', '#DDAA11', '#FFCC00'] # blue sky bg.fill(292) # brown bricks on the ground bg[10] = 9 * [436, 437] bg[11] = 9 * [438, 439] # little green hill bg[8, 3:5] = [305, 306] bg[9, 2:6] = [304, 308, 294, 307] bg_colors[8, 3:5] = [0, 1, 4, 3] bg_colors[9, 2:6] = [0, 1, 4, 3] # brown bricks bg[2, 10:18] = 325 bg[3, 10:18] = 327 # gold question block bg[2, 12:14] = [339, 340] bg[3, 12:14] = [341, 342] bg_colors[2:4, 12:14] = [0, 6, 2, 3] # duplicate background for clean wrapping bg = np.hstack([bg, bg]) bg_colors = np.hstack([bg_colors, bg_colors]) # get index of yellow pixels to make them flash i_yellow = np.where(bg_colors == 6) # create background frames by offsetting the image for offset in range(36): bg_colors[i_yellow] = [6, 6, 6, 6, 5, 5, 2, 5, 5][offset % 9] NA.add_frame('bg', bg, bg_colors, bg_ctable, offset=(0, -0.5 * offset), transparent=False) # Create mario frames mario_colors = ['white', 'red', 'orange', 'brown'] NA.add_frame('mario', [[0, 1], [2, 3], [4, 5], [6, 7]], ctable=mario_colors, offset=(2, 10)) NA.add_frame('mario', [[8, 9], [10, 11], [12, 13], [14, 15]], ctable=mario_colors, offset=(2, 10)) NA.add_frame('mario', [[16, 17], [18, 19], [20, 21], [22, 23]], ctable=mario_colors, offset=(2, 10)) # Create koopa-troopa frames troopa_colors = ['white', 'green', 'white', 'orange'] NA.add_frame('troopa', [[252, 160], [161, 162], [163, 164]], ctable=troopa_colors, offset=(2, 7)) NA.add_frame('troopa', [[252, 165], [166, 167], [168, 169]], ctable=troopa_colors, offset=(2, 7)) # Create goomba frames goomba_colors = ['white', 'black', '#EECCCC', '#BB3333'] NA.add_frame('goomba', [[112, 113], [114, 115]], ctable=goomba_colors, offset=(2, 4)) NA.add_frame('goomba', [[112, 113], [-115, -114]], ctable=goomba_colors, offset=(2, 4)) return NA.animate(interval=100, frames=36) if __name__ == '__main__': anim = animate_mario() # saving as animated gif requires matplotlib 0.13+ and imagemagick #anim.save('mario_animation.gif', writer='imagemagick', fps=10) plt.show()
The result looks like this:
Pretty good! With a bit more work, it would be relatively straightforward to use the above code to do some more sophisticated animations: perhaps recreate a full level from the original Super Mario Bros, or even design your own custom level. You might think about taking the extra step and trying to make Mario's movements interactive. This could be a lot of fun, but probably very difficult to do well within matplotlib. For tackling an interactive mario in Python, another framework such as Tkinter or pygame might be a better choice.
I hope you enjoyed this one as much as I did -- happy coding! | https://jakevdp.github.io/blog/2013/01/13/hacking-super-mario-bros-with-python/ | CC-MAIN-2018-39 | refinedweb | 2,227 | 57.06 |
Using custom Django URL path convertersdjangopythonweb development
Photo by Luemen Rutkowski on Unsplash
You will very likely have seen Django's standard converters when building your URL patterns.
For example:
# urls.py
from django.urls import path
from myapp.views import post_detail
urlpatterns = [
path('posts/<int:post_id>/', post_detail, name="post_detail"),
]
The parameter post_id will be automatically converted to an
int in your view args:
def post_detail(request, post_id: int):
...
This functionality is handled by a converter, in this case the
IntConverter, mapped to the namespace int:
class IntConverter:
regex = '[0-9]+'
def to_python(self, value):
return int(value)
def to_url(self, value):
return str(value)
The converter class must provide a
to_python() method that takes a string and converts it to some other value (in this case an
int) and a
to_url() method that takes a Python value and converts it into a URL path-friendly string. You also need a
regex property that allows Django's router to identify this converter when parsing the inbound URL.
You can see other examples here.
Suppose you want to make your own custom converter? Let's say you have a use case where you want to add a date string to your path, and have Django convert that to a
datetime.date instance as a view parameter. For example:
The string 2022-02-17 is automatically converted to a
datetime.date object in your view:
def post_archive(request, archive_date: date):
...
To get this to work, we need to create a custom converter class, and then register it with Django:
# urls.py
from django.urls import path
from datetime import date, datetime
from myapp.views import post_detail, post_archive
class DateConverter:
regex = r"\d{4}-\d{1,2}-\d{1,2}"
format = "%Y-%m-%d"
def to_python(self, value: str) -> date:
return datetime.strptime(value, self.format).date()
def to_url(self, value: date) -> str:
return value.strftime(self.format)
register_converter(DateConverter, "date")
urlpatterns = [
path('posts/<int:post_id>/', post_detail, name="post_detail"),
path('posts/archive/<date:archive_date>/', post_archive, name="post_archive"),
]
The
DateConverter class is registered with the
register_converter() function with the namespace "date". The regex will look for the pattern YYYY-MM-DD in the URL, and the parameter will be automatically converted into a
datetime.date object.
The
to_url() method on the other hand works in reverse. For example you can write:
from datetime import date
from django.urls import reverse
reverse("post_archive", args=[date(year=2022, month=2, day=17)])
and you will get the output /posts/archive/2022-02-17/.
One further note: if the
to_python() method raises a
ValueError, Django will raise a
404 NOT FOUND. For example, if you try and create a
datetime from an invalid date string,
strptime() raises a
ValueError:
from datetime import datetime
datetime.strptime("2022-2-33", "%Y-%m-%d")
So this URL, even though it matches the
DateConverter regex, will still raise a 404:
Therefore take care that your
to_python() method either implicitly or explicitly raises a
ValueError if the conversion fails.
- Next: Notes on Learning Finnish
- Previous: Run a self-hosted PAAS with Dokku | https://danjacob.net/posts/djangocustomconverters/ | CC-MAIN-2022-40 | refinedweb | 510 | 55.13 |
From the README of CBOOCall.jl:
split(",", "a,b,c") is not really the right way to do it.
split only works with strings, so it should be a class method.
We should be able to do
",".split("a,b,c").
There’s even a mnemonic. Think of “comma-separated values”.
Well this is a “comma split string”.
Now there is a way with
CBOOCall.jl:
julia> @eval Base import CBOOCall; julia> @eval Base CBOOCall.@cbooify String (split,)
Then we have
julia> ",".split("a,b,c") 1-element Vector{SubString{String}}: ","
… uh, we can fix that
julia> @eval Base CBOOCall.@cbooify String (split=(x,y) -> split(y, x),) julia> ",".split("a,b,c") 3-element Vector{SubString{String}}: "a" "b" "c"
Ahhhh… That’s much better than
split("a,b,c", ",")! …
I mean
split(",", "a,b,c").
… wait …, is, … it’s the other way around, right? Let’s consult the Zen of CBOO.
>>> spl[TAB, TAB] # Bonk! Bonk! It's not there. >>> from string import spl[TAB, TAB] # Bonk! Bonk! Not there either. Good. >>> ','.split("a,b,c") [','] >>> 'a,b,c'.split(",") ['a', "b", 'c']
So the first way was correct. In any case, this is clearly the superior, intuitive, syntax for splitting strings.
Of course, you have to pay for this with a performance hit, right? How much is it?
Let’s pick a fast operation, and put it in the middle of a list, and swap parameter order for no reason.
julia> @eval Base CBOOCall.@cbooify Int64 (+, /, length, xor=(x,y)->xor(y,x), floor, rand)
The usual way
julia> @btime sum(xor(x,y) for (x, y) in zip(1:100, 101:200)) 2.134 ns (0 allocations: 0 bytes) 16856
The way of CBOO
julia> @btime sum(x.xor(y) for (x, y) in zip(1:100, 101:200)) 2.134 ns (0 allocations: 0 bytes) 16856
Why does this work ? Someone made searching for a literal
Symbol in a
Tuple of
Symbols very fast in order to make
NamedTuples fast.
julia> @btime in(3, (1,2,3)) 1.442 ns (0 allocations: 0 bytes) true julia> @btime in(:a, (:b, :c, :a)) 0.020 ns (0 allocations: 0 bytes) true
(The for-real README gives the real motivation, which is to avoid namespace pollution) | https://discourse.julialang.org/t/ann-cboocall/81420 | CC-MAIN-2022-27 | refinedweb | 379 | 87.62 |
Hi
I have done the following code to find the Nth Fibonacci number. It works. But now I need to do find the Nth Fibonacci number using recursion. How do I do this?
I found the following link but still couldn't understand what to do? Please help me. Thanks a lot.
Link: Recursive Fibonacci Sequence - C++ - Source Code | DreamInCode.net
Code:// fibo_recursion_simple.cpp // finding nth Fibonacci number #include <iostream> #include <cstdlib> using namespace std; unsigned long fibo(unsigned long n); int main() { int n; unsigned long answer; cout << "which Fibonacci number to find, e.g 5th,: "; cin >> n; answer = fibo(n); cout << n << "th Fibonacci number is: " << answer << endl; system("pause"); return 0; } //------------------------------------------------------ // fibo() definition unsigned long fibo(unsigned long n) { if (n >= 3) { // fibo(n) = fibo(n-1) + fibo(n-2) const unsigned long limit = 4294967295; unsigned long next_to_last = 0; unsigned long last = 1; int i = 0; while( next_to_last < limit/2 ) { long new_last = next_to_last + last; next_to_last = last; last = new_last; i = i++; if ( i == n ) { break; } } return (next_to_last); } else { return 1; } } | http://cboard.cprogramming.com/cplusplus-programming/138205-nth-fibonacci-number-using-recursion.html | CC-MAIN-2015-32 | refinedweb | 172 | 63.9 |
As we get closer to the launch of VS2010 I’m covering some of my favorite new feature areas for VS2010. For this post I’m going to talk about Dependency Graphs and it’s underlying support, DGML.
Generating Graphs
At some point I’m sure you’ve joined a team (or inherited a code base) which you did not create. I’m guessing there is a good chance you didn’t wind up getting a fantastic set of documentation or architecture for some of those projects. Wouldn’t you love to start by understanding what you’ve just gotten yourself into? This is where Dependency Graphs come in.
Generating a dependency graph with VS2010 Ultimate is easy using the Architecture, Generate Dependency Graph menu:
In this case we’ll look at the diagram by namespace using the Tailspin sample application. VS will walk through the binaries of the program looking for all of the dependencies and generate a DGML file with the data. The top level view will start off with the namespace dependencies at the highest level (assembly boundary):
From here you can navigate dependencies and drill down to more detailed information. Simply hovering over an item will give detailed information about that item. Hovering over a link will also provide additional information about the type of link (such as a method call or reference). Clicking the expand button will update the graph to show the next level of detail:
You can continue to explore links and items to an increasing level of granularity. In this example the classes in a namespace are shown:
You can continue to drill down all the way to the source code itself.
Architectural Explorer
Now that we have our visual view of the system, we can also use the Architectural Explorer to spelunk through our application. Activating the explorer is easy:
The explorer window allows you to drill down on the contents by clicking as well as with filtering. In this case we’ll find any class with ‘Model’ in the name and further drill down to the definitions in the class:
This support is customizable and allows you to author queries you can re-run later.
DGML
Dependency Graphs are stored in XML using the DGML DOM. Using DGML is very easy (Cameron has a getting started post here). If you open the example above, you’ll find all the raw data for the Tailspin application:
This makes the system incredibly powerful because the DGML viewer in Visual Studio can be used to view any DGML document, including content you produce from your own tools. As an example, VS ships with a built-in help file that explains how to use the mouse to interact with the DGML viewer. That file itself is a DGML file:
There are many easy extensibility points with the system. As an example we’ve had 3rd parties augment the dependency graph information to include more data such as runtime profiling coverage.
Summary
This is just a few examples of the new ways to explore your existing software. In addition to helping you understand the system, we want to provide tools that allow you to evolve the architecture (or fix as necessary). That support includes being able to describe the logical tiers of your application and enforcement of layering with new changes.
To learn more, check out these great links:
Thanks for the write up.
Interestingly very similar to the NDepend Tool.
Is this something which will be delivered OOB within VS 2010 ?
@Raghuraman:
Looks like it comes with VS Ultimate only, a (by current MSDN prices) 6,000 to 10,000 dollar purchase.
Nice, but since it is basically unaffordable to the majority of developers, it becomes a meaningless feature.
The DGML viewer is a great tool. I can think of many applications outside of Application Architecture where it would be useful.
I agree with the other posters that the full potential of this technology will not be realized if the price point is the cost of VS Ultimate.
I would hope that the viewer would be made available as a GUI Control (which I assume is how VS Ultimate uses it). Then developers could purchase a dev license to include the viewer in our own apps (the control should come free with Ultimate).
Does anybody know if providing the viewer as a control is planned?
Very nice. But why must you taunt us this way?
As indicated, this would have value to anybody that’s inherited code for maintenance i.e, NOT architects). But as others have stated, limited to Ultimate edition guarantees most will never even see this feature.
When presenting new features limited in edition (especially to Ultimate/Team Systems), please (all MS folks) state that limitation up front.
To be fair Nunya, the article does state VS 2010 Ultimate although it is a kind of throwaway statement. I, and I’m sure many other developers, are in the fortunate position of being supported by a large comapny with sufficient budget to provide us with VS 2010 Ultimate and we are certainly going to get some benefit from this tool. At the end of the day, if there are going to be variants of the IDE aimed at differently budgeted groups of developers some folks are going to have to expect to miss out on some of the goodies.
they change the name of software then resell
Is this gone a work with native C++ ?
@Frederic
We recognize the need to make this work for native C++ however with RTM, you won’t see these features. Stay tuned though!
Boris Jabes
Visual C++ Team
This looks wonderful. Will it be possible to use Visual Studio’s DGML viewer in our own applications, much like how the Workflow designer is reusable?
I think feature would rock like anything. Seriously programming using some open source libraries is always been pain as there is not sufficient documentation. But, this feature would help in having a quick overview of the entire library.
eagerly waiting to get my hands on RC.
🙂
I got a question in email on how to get the help.dgml in the product. My response in email bounced off the server so I’m posting the answer here:
1. Right click, Add > New item
2. Pick "Directed Graph Document", add
3. On the empty page you will find "For help about browsing the graph with the mouse, click here"
At that point just click the ‘here’ hotlink and it will pop up. | https://blogs.msdn.microsoft.com/jasonz/2010/02/02/favorite-vs2010-features-dependency-graphs-and-dgml/ | CC-MAIN-2016-50 | refinedweb | 1,089 | 61.67 |
Who's Afraid of a Big Bad Bond Bump? (Not China)
Bad news can be good.Photographer: Qilai Shen
China was supposed to be the loser after Moody's Investors Service lowered its rating on Chinese government debt for the first time since 1989. The May 24 downgrade to A1 from Aa3 was widely reported as an ominous turn for the world's second-largest economy, whose credit was said to be deteriorating amid borrowing problems and slower growth.
Moody's decision will "deal a blow to confidence in regional markets," Jingyi Pan, a market strategist at IG Asia Pte Ltd, told the Associated Press, predicting that "the attention on China's worsening outlook could create jitters."
Almost two months later, China is outperforming the emerging market with its bonds, stocks and currency. A buyer of $1 million worth of Chinese government securities on the day Moody's said they were less secure now has a profit of $25,000, or a total return of 2.5 percent. An equivalent purchase of emerging market sovereign debt would have returned only $9,000, or 0.9 percent.
Bad Bond News Is Good News for China
Bloomberg Barclays China Aggregate Index, July 2015 to July 2017
Source: Bloomberg
Stocks of Chinese companies are beating competitors, too, since Moody's delivered its bad news. The 300 companies in the Shanghai Shenzhen CSI 300 are up 9.5 percent, while indices for the emerging market and S&P 500 gained 3.7 percent and 2.2 percent respectively. The currency has rallied 1.4 percent, more than half its appreciation of 2.3 percent this year, according to data compiled by Bloomberg.
China, with its huge economy, sophisticated financial management and vast domestic resources, is the latest country to turn sovereign-debt ratings on their heads. Global investors know its strengths and have little interest in the opinions of bond-rating companies, just as they made an absurdity of downgrades on Austria, Finland, France, Greece, Japan, New Zealand and the U.S. during the past six years. Every one of these economically advanced countries saw prices on their bonds rise and interest rates fall during the 200 days following the downgrade.
An investment of 1 million euros in Greek bonds on April 29, 2015, when Moody's lowered Greece to a non-investment-grade category with greater risk of default, is worth 1,717,000 euros today; that's a total return (income plus appreciation) of 71.7 percent. Putting the same amount into Eurozone sovereign debt over the same period returned only 0.4 percent, according to data compiled by Bloomberg.
When the Treasury sold $29 billion of seven-year notes in May 2012, nine months after Standard & Poor's said the U.S. was a less-creditworthy AA+ instead of AAA, their value had never been higher, with a record-low interest rate of 1.2 percent. Today's 2.33 percent yield on 10-year government bonds still is lower than the 2.96 percent on July 14, 2011, when S&P said it would downgrade the No. 1 economy, and the 2.56 percent yield on Aug. 5, when S&P actually did so. The buyer of $1 million of those securities six years ago has earned $125,000 since then, or 12.5 percent, while an investor in the same amount of global government bonds over the same period lost $983,000, or a total return of minus 1.6 percent, according to data compiled by Bloomberg.
China is proving no different. Its bonds have appreciated 2.5 percent since the May downgrade and are No. 3 among the 19 developing countries included in the emerging market for sovereign debt, which shows a total return of 0.9 percent, according to the Bloomberg Barclays EM Local Currency Government + China Index.
With Chinese securities strong, premiums paid by investors as insurance against their loss of value grew cheaper. Credit default swaps on Chinese government debt declined 13 percent after the May downgrade, to the lowest level since 2013, according to data compiled by Bloomberg. That's partly because potential lenders grew more confident about the creditworthiness of 51 companies owned by the central government. That's based on a measure of risk showing that the average probability of default in one year has declined to 0.19 percent, the lowest level since 2007, from 1.1 percent early last year, according to data compiled by Bloomberg.
The improved credit profile is a consequence of declining debt to equity ratios and narrower price fluctuations in the stock market, where government-owned PetroChina Company Limited has the lowest such ratio since 2011. The probability of default in one year for another major government-owned company, China Petroleum & Chemical Corp., has fallen to 0.02 percent from 0.16 percent last year, its lowest debt to equity ratio since 2002 when such data became available, according to data compiled by Bloomberg.
On June 20, less than a month after Moody's downgrade of China, the people responsible for compiling the MSCI Emerging Market Index announced that China's A shares will be included in the benchmark index for the first time after three years of rejections -- all but inviting global investors to consider the Moody's downgrade a contrary indicator.
"I'd say there's a lot of confidence in China," said Lloyd C. Blankfein, chairman and chief executive officer of Goldman Sachs Group Inc., on June 28 after a recent visit. "China is almost an island of stability" he says in a video prepared by his firm
(With assistance from Shin Pei)
This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.
To contact the editor responsible for this story:
Jonathan Landman at jlandman4@bloomberg.net | https://www.bloomberg.com/view/articles/2017-07-13/who-s-afraid-of-a-big-bad-bond-bump-not-china | CC-MAIN-2018-17 | refinedweb | 972 | 63.19 |
Pandas Difference Between two Dataframes
There are often cases where we need to find out the common rows between the two dataframes or find the rows which are in one dataframe and missing from second dataframe. In this post we will see how using pandas we can achieve this.
Here are two dataframes which we will use to find common rows, Rows in dataframe 1 and Rows in dataframe 2
import pandas as pd df1 = pd.DataFrame({'City': ['New York', 'Chicago', 'Tokyo', 'Paris','New Delhi'], 'Temp': [59, 29, 73, 56,48]}) df2 = pd.DataFrame({'City': ['London', 'New York', 'Tokyo', 'New Delhi','Paris'], 'Temp': [55, 55, 73, 85,56]})
Find Common Rows between two Dataframe Using Merge Function
Using the merge function you can get the matching rows between the two dataframes. So we are merging dataframe(df1) with dataframe(df2) and Type of merge to be performed is inner, which use intersection of keys from both frames, similar to a SQL inner join.
df = df1.merge(df2, how = 'inner' ,indicator=False) df
So what we get is Tokyo and Paris which is common between the two dataframes
Find Common Rows Between Two Dataframes Using Concat Function
The concat function concatenate second dataframe(df2) below the first dataframe(df1) along a particular axis with optional set logic along the other axes. So here we are concating the two dataframes and then grouping on all the columns and find rows which have count greater than 1 because those are the rows common to both the dataframes. here is code snippet:
df = pd.concat([df1, df2]) df = df.reset_index(drop=True) df_gpby = df.groupby(list(df.columns)) idx = [x[0] for x in df_gpby.groups.values() if len(x) != 1] df.reindex(idx)
Find Rows in DF1 Which Are Not Available in DF2
We will see how to get all the rows in dataframe(df1) which are not available in dataframe(df2). We can use the same merge function as used above only the parameter indicator is set to true, which adds a column to output DataFrame called “_merge” with information on the source of each row. If string, column with information on source of each row will be added to output DataFrame, and column will be named value of string. Information column is Categorical-type and takes on a value of “left_only” for observations whose merge key only appears in ‘left’ DataFrame, “right_only” for observations whose merge key only appears in ‘right’ DataFrame, and “both” if the observation’s merge key is found in both
df = df1.merge(df2, how = 'outer' ,indicator=True).loc[lambda x : x['_merge']=='left_only'] df
Using the lambda function we have filtered the rows with _merge value “left_only” to get all the rows in df1 which are missing from df2
Find Rows in DF2 Which Are Not Available in DF1
Just change the filter value on _merge column to right_only to get all the rows which are available in dataframe(df2) only and missing from df1
Just see the type of merge i.e. parameter how is changed to outer which is basically union of keys from both frames, similar to a SQL full outer join
df = df1.merge(df2, how = 'outer' ,indicator=True).loc[lambda x : x['_merge']=='right_only'] df
Check If Two Dataframes Are Exactly Same
In order to check if two dataframes are equal we can use equals function, which llows
df2.equals(df1) False
Check If Columns of Two Dataframes Are Exactly Same
Using equals you can also compare if the columns of two dataframes are equal or not
df2['Temp'].equals(df1['Temp']) False
Find Rows Which Are Not common Between Two dataframes
So far we have seen all the ways to find common rows between two dataframes or rows available in one and missing from another dataframe. Now if we have to get all the rows which are not common between the two dataframe or we want to see all the unique un-matched rows between two dataframe then we can use the concat function with drop_duplicate.
pd.concat([df1,df2]).drop_duplicates(keep=False)
Find All Values in a Column Between Two Dataframes Which Are Not Common
We will see how to get the set of values between columns of two dataframes which aren’t common between them. So here we are finding the symmetric difference also known as the disjunctive union, of two sets is the set of elements which are in either of the sets and not in their intersection
set(df1.Temp).symmetric_difference(df2.Temp) {29, 48, 55, 59, 85}
The above line of code gives the not common temperature values between two dataframe and same column. Check df1 and df2 and see if the uncommon values are same.
Conclusion
So we have seen using Pandas - Merge, Concat and Equals how we can easily find the difference between two excel, csv’s stored in dataframes. Also it gives an intuitive way to compare the dataframes and find the rows which are common or uncommon between two dataframes. You can also read this post and see how two exel files can be compared using pandas cell by cell and store the results in an excel report. | https://kanoki.org/2019/07/04/pandas-difference-between-two-dataframes/ | CC-MAIN-2022-33 | refinedweb | 867 | 63.12 |
A Python parser for the journald binary export format
This is a really simple Python parser for the journald binary export format.
It can parse journal entries from a file-like object or an iterable, and yields each entry as a dict containing all attributes of the journal entry:
from __future__ import print_function # if using Python 2.x from journalparse import journalparse with open("some_file", "rb") as fp: for entry in journalparse(fp): print(entry) # ... or ... data = b"_MESSAGE=blah" for entry in journalparse(data): print(entry)
There are no requirements other than Python. Tested on Python 3.5 but should work on Python 2.6+ and 3.2+.
Download the file for your platform. If you're not sure which to choose, learn more about installing packages. | https://pypi.org/project/journalparse/ | CC-MAIN-2017-30 | refinedweb | 128 | 58.48 |
If we have an array[5], we know that arr == &arr[0]
but what is &arr[2] = ?
Also, what does &arr return to us?
Let's look at a simple example first:
int a; a = 5;
In a sense the integer a has two values assoicated with it. The one you most likely think about first is the rvalue, which in this case is the number 5. There is also what is called an lvalue (pronounced "el value") which is the memory address the integer a is located at.
This is an important concept to grasp. At the end of the day everything is all about memory. We store code and variables in memory. The CPU executes instructions which are located in memory and it performs actions on data which is also in memory. It's all just memory. Nothing very complicated; if someone tries to scare you with pointers don't listen, it's all just memory :)
Alrighty so, in the case of an array we are dealing with a contiguious block of memory that is used for storing data of the same type:
int array[] = {0, 1, 1, 2, 3, 5, 8, 13, 21};
As you have already noted the name of the array refers to the memory location of the first element in the array (e.g. array == &array[0]). So in my example array above &array[2] would refer to the memory location (or lvalue) that contains the third element in the array.
To answer your other question &array is just another memory address, see if this code snippet helps clear up what it points to :)
#include <stdio.h> #include <stdlib.h> int array[] = {0, 1, 1, 2, 3, 5, 8, 13, 21}; int main(void) { printf("&array[2] is: %p\n", &array[2]); printf("&array[0] is: %p\n", &array[0]); printf("&array is: %14p\n", &array); exit(0); } % gcc test.c % ./a.out &array[2] is: 0x100001088 &array[0] is: 0x100001080 &array is: 0x100001080 | https://codedump.io/share/lJEBAao5uTZ6/1/in-an-array-what-does-amparr2-return | CC-MAIN-2017-09 | refinedweb | 330 | 69.21 |
*Redis Mass Insertion
Sometimes Redis instances needs to be loaded with big amount of preexisting or user generated data in a short amount of time, so that millions of keys will be created as fast as possible.
This is called a mass insertion, and the goal of this document is to provide information about how to feed Redis with data as fast as possible.
*Use the protocol, Luke
Using a normal Redis client to perform mass insertion is not a good idea for a few reasons: the naive approach of sending one command after the other is slow because you have to pay for the round trip time for every command. It is possible to use pipelining, but for mass insertion of many records you need to write new commands while you read replies at the same time to make sure you are inserting as fast as possible.
Only a small percentage of clients support non-blocking I/O, and not all the clients are able to parse the replies in an efficient way in order to maximize throughput. For all this reasons the preferred way to mass import data into Redis is to generate a text file containing the Redis protocol, in raw format, in order to call the commands needed to insert the required data.
For instance if I need to generate a large data set where there are billions of keys in the form: `keyN -> ValueN' I will create a file containing the following commands in the Redis protocol format:
SET Key0 Value0 SET Key1 Value1 ... SET KeyN ValueN
Once this file is created, the remaining action is to feed it to Redis
as fast as possible. In the past the way to do this was to use the
netcat with the following command:
(cat data.txt; sleep 10) | nc localhost 6379 > /dev/null
However this is not a very reliable way to perform mass import because netcat
does not really know when all the data was transferred and can't check for
errors. In 2.6 or later versions of Redis the
redis-cli utility
supports a new mode called pipe mode that was designed in order to perform
mass insertion.
Using the pipe mode the command to run looks like the following:
cat data.txt | redis-cli --pipe
That will produce an output similar to this:
All data transferred. Waiting for the last reply... Last reply received from server. errors: 0, replies: 1000000
The redis-cli utility will also make sure to only redirect errors received from the Redis instance to the standard output.
*Generating Redis Protocol
The Redis protocol is extremely simple to generate and parse, and is Documented here. However in order to generate protocol for the goal of mass insertion you don't need to understand every detail of the protocol, but just that every command is represented in the following way:
*<args><cr><lf> $<len><cr><lf> <arg0><cr><lf> <arg1><cr><lf> ... <argN><cr><lf>
Where
<cr> means "\r" (or ASCII character 13) and
<lf> means "\n" (or ASCII character 10).
For instance the command SET key value is represented by the following protocol:
*3<cr><lf> $3<cr><lf> SET<cr><lf> $3<cr><lf> key<cr><lf> $5<cr><lf> value<cr><lf>
Or represented as a quoted string:
"*3\r\n$3\r\nSET\r\n$3\r\nkey\r\n$5\r\nvalue\r\n"
The file you need to generate for mass insertion is just composed of commands represented in the above way, one after the other.
The following Ruby function generates valid protocol:
def gen_redis_proto(*cmd) proto = "" proto << "*"+cmd.length.to_s+"\r\n" cmd.each{|arg| proto << "$"+arg.to_s.bytesize.to_s+"\r\n" proto << arg.to_s+"\r\n" } proto end puts gen_redis_proto("SET","mykey","Hello World!").inspect
Using the above function it is possible to easily generate the key value pairs in the above example, with this program:
(0...1000).each{|n| STDOUT.write(gen_redis_proto("SET","Key#{n}","Value#{n}")) }
We can run the program directly in pipe to redis-cli in order to perform our first mass import session.
$ ruby proto.rb | redis-cli --pipe All data transferred. Waiting for the last reply... Last reply received from server. errors: 0, replies: 1000
*How the pipe mode works under the hoods
The magic needed inside the pipe mode of redis-cli is to be as fast as netcat and still be able to understand when the last reply was sent by the server at the same time.
This is obtained in the following way:
- redis-cli --pipe tries to send data as fast as possible to the server.
- At the same time it reads data when available, trying to parse it.
- Once there is no more data to read from stdin, it sends a special ECHO command with a random 20 bytes string: we are sure this is the latest command sent, and we are sure we can match the reply checking if we receive the same 20 bytes as a bulk reply.
- Once this special final command is sent, the code receiving replies starts to match replies with this 20 bytes. When the matching reply is reached it can exit with success.
Using this trick we don't need to parse the protocol we send to the server in order to understand how many commands we are sending, but just the replies.
However while parsing the replies we take a counter of all the replies parsed so that at the end we are able to tell the user the amount of commands transferred to the server by the mass insert session. | http://redis.io/topics/mass-insert | CC-MAIN-2016-26 | refinedweb | 938 | 56.59 |
XPath is the XML Path Language for defining how a specific element in a XML document can be located. It's sort of like the '#' convention in HTML URLs but for XML.
XPath is a defines a syntax and specification for addressing
different parts of an XML document. It can also be used to address
functions in a library.
An XPath expression, when evaluated, results in a set of nodes, a
boolean, a number, or a string. XPath expressions are evaluated in a
context, which in most cases will be some node (the context node), but
which can also be a namespace, a function library, a set of variable
bindings, or a pair of non-zero integers (context position and
size).
The context is usually determined by the system doing the
processing; a XSLT processor for instance.
The nodes in this metanode will sometimes refer to this document fragment to provide some
examples:
<zoo>
<animals>
<dog breed="collie">
<cat breed="tabby">
</animals>
<people>
<person name="John" job="keeper">
<person name="Amy" job="vet">
</people>
</zoo>
Most of this information is condensed from the XPath specs at and from articles on.
Log in or register to write something here or to contact authors.
Need help? accounthelp@everything2.com | https://everything2.com/title/XPath | CC-MAIN-2017-43 | refinedweb | 207 | 57.71 |
Passwd::DB provides basic password routines. It augments getpwnam and getpwuid functions with setpwinfo, modpwinfo, rmpwnam, mgetpwnam. The routines can be used both in object context or straight. When used in non-object context a call to init_db is ...EESTABROO/Passwd-DB-1.03 - 30 Jun 2008 23:34:16 GMT - Search in distribution
: add a data source to the current namespace...BRUMMETT/UR-0.43 - 03 Jul 2014 14:36:23 GMT - Search in distribution
- UR::Object::Type::Initializer - Class definition syntax
- Oryx::Class - abstract base class for Oryx
JOHNH/Fsdb-2.56 - 04 Feb 2015 05:59:10 GMT - Search in distribution
- dbrowenumerate - enumerate rows, starting from zero
- Fsdb::Filter::dbrow - select rows from an Fsdb file based on arbitrary conditions
- Fsdb::Filter::db_to_html_table - convert db to an HTML table
Db::DFC provides an object-oriented interface to Documentum's DFC. ......MSROTH/Db-DFC-0.4 - 06 Mar 2001 13:26:21 GMT - Search in distribution
HDELGADO/DBIx-Fast-0.06 - 20 Mar 2015 01:01:55
- csl_query - example command-line interface to CPAN::Search::Lite::Query
- Apache2::CPAN::Search - mod_perl interface to CPAN::Search::Lite::Query
- CPAN::Search::Lite::Query - perform queries on the database
- 1 more result from CPAN-Search-Lite »
******************************************************************* *** *** *** NOTE: This is a very early release that may contain lots of *** *** bugs. The API is not stable and may change between releases *** *** *** ******************************...SALVA/Pg-PQ-0.14 - 28 Oct 2014 17:00:59 (1 review) - 05 Apr 2010 18:43:52
Perl lets us have complex data structures. You can write something like this and all of a sudden, you'd have an array with three dimensions! for $x (1 .. 10) { for $y (1 .. 10) { for $z (1 .. 10) { $AoA[$x][$y][$z] = $x ** $y + $z; } } } Alas, howeve...SHAY/perl-5.20.2 (6 reviews) - 14 Feb 2015 18:27:06 GMT - Search in distribution
- perlfunc - Perl builtin functions
- perl56delta - what's new for perl v5.6.0
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Synctree brings a VOB area into alignment with a specified set of files from a source area. It's analogous in various ways to *clearfsimport*, *citree*, and *clearexport/clearimport*; see the COMPARISONS section below. Synctree is useful if you have ...DSB/ClearCase-SyncTree-0.60 - 08 Aug 2013 21:05:15 GMT - Search in distribution - Search in distribution
MQSERIES/MQSeries-1.34 (4 reviews) - 13 Dec 2012 19:19:56 GMT - Search in distribution
ABBYPAN/SimpleDBI-0.02 - 22 Jan 2015 01:40:27 GMT - Search in distribution | https://metacpan.org/search?q=Passwd-DB | CC-MAIN-2015-18 | refinedweb | 421 | 57.87 |
xdiagnose has a symlink attack due to improperly named file in /tmp
Bug Description
The code already says it, mktemp should be used to direct the output of the commands to a secure location instead of /tmp .
/usr/lib/
def on_make_
execute("tar -cf %s %s" %(xorg_backup_file, xorg_backup_dir))
Please raise the priority! It's not clear at all why we should assume that kernel hardening will guarantee that no path writable by the process in a symlink attack will be harmful. And I don't believe there is any apparmor rules for this in any case.
Because it's a security issue, it should be fixed, and not just postponed until some other security task is done.
Bryce can you comment on the patch? As written, it won't clean up after itself and there is a TODO in the code to implement this in the way Alec suggested. I'm not sure why it wasn't implemented like this to begin with if there wasn't some cleanup or other reason that needed to also be done.
Yeah, sheer laziness on my part.
This bit of code is actually exceedingly unimportant. The tarball that is generated is purely for the user's use and is not uploaded anywhere or made use of in any form by xdiagnose. It was a community contribution from back in the days before we had a decent X apport hook. Now days we'd just have them file a bug via ubuntu-bug xorg. I suppose users might not have apport turned on or something, so this might conceivably still be of some use, however I see the function's begun to bitrot: it's looking for gdm rather than lightdm.
So, I think the right thing to do here is rather than fix the temp file, to just excise the functionality and focus on apport as the way to gather troubleshooting info.
Note that the original patch is against welcome.py, which isn't used by anything. The code is a partial rewrite of Failsafe-X into python, but it's still not quite done so I haven't switched over to it. And like I mentioned, that particular functionality is obsolete by apport now so should just go.
I've posted three commits to xdiagnose trunk:
http://
- This one just gets rid of the code from welcome.py. This is probably adequate to eliminate the security issue. Since like I said, this is not user facing at all, it causes no functional loss and thus should be no risk to backport to precise.
http://
- This drops the same functionality from the actual failsafe-X code that is user facing. This particular chunk of code doesn't have the security flaw (it calls mktemp properly). So not really a need to backport this. But you're welcome to if you'd like. I've tested that failsafe-x still works properly with this removed.
http://
- Changelog updates for above two changes.
jdstrand, go ahead and pick what you want from the above for past releases.
I'll roll the above out to quantal either today or tomorrow.
Code is not present in 11.10 and earlier.
As the commit was made publicly, marking the bug public. I will push this out to 12.04 LTS tomorrow. Bryce, feel free to upload to 12.10.
The attachment "Use tempfile.mkdtemp to make a secure temp xdiagnose - 3.2
---------------/
auto-collected crash bugs.
(LP: #1036114)
-- Bryce Harrington <email address hidden> Tue, 25 Sep 2012 11:16:30 -0700
This bug was fixed in the package xdiagnose - 2.5.2ubuntu0.1
---------------
xdiagnose (2.5.2ubuntu0.1) precise-security; urgency=low
* SECURITY UPDATE: fix insecure temporary file creation
- xdiagnose/
as people should be using 'ubuntu-bug xorg' anyway. Patch thanks
to Bryce Harrington.
- CVE-2012-XXXX
- LP: #1036211
-- Jamie Strandboge <email address hidden> Mon, 01 Oct 2012 17:04:28 -0500
Thank you for using Ubuntu and reporting a bug. Ubuntu's kernel hardening should prevent attacks against xdiagnose. So I'll mark this as Low for now. Subscribing Bryce. | https://bugs.launchpad.net/ubuntu/+source/xdiagnose/+bug/1036211 | CC-MAIN-2016-50 | refinedweb | 683 | 74.49 |
Web scraping is where a programmer will write an application to download web pages and parse out specific information from them. Usually when you are scraping data, you will need to make your application navigate the website programmatically. In this article,!
Preparing to Scrape
Before we can start scraping, we need to figure out what we want to do. We will be using my blog for this example. Our task will be to scrape the titles and links to the articles on the front page of this blog. You can use Python’s urllib2 module to download the HTML that we need to parse or you can use the requests library. For this example, I’ll be using requests.
Most websites nowadays have pretty complex HTML. Fortunately, most browsers provide tools to make figuring out where website elements are quite trivial. For example, if you open my blog in chrome, you can right click on any of the article titles and click the Inspect menu option (see below):
Once you’ve clicked that, you will see a sidebar appear that highlights the tag that contains the title. It looks like this:
The Mozilla Firefox browser has Developer tools that you can enable on a per page basis that includes an Inspector you can use in much the same way as we did in Chrome. Regardless which web browser you end up using, you will quickly see that the h1 tag is the one we need to look for. Now that we know what we want to parse, we can learn how to do so!
BeautifulSoup
One of the most popular HTML parsers for Python is called BeautifulSoup. It’s been around for quite some time and is known for being able to handle malformed HTML well. To install it for Python 3, all you need to do is the following:
pip install beautifulsoup4
If everything worked correctly, you should now have BeautifulSoupinstalled. When passing BeautifulSoup some HTML to parse, you can specify a tree builder. For this example we will use html.parser, because it is included with Python. If you’d like something faster, you can install lxml.
Let’s actually take a look at some code to see how this all works:
import requests from bs4 import BeautifulSoup url = '' def get_articles(): """ Get the articles from the front page of the blog """ req = requests.get(url) html = req.text soup = BeautifulSoup(html, 'html.parser') pages = soup.findAll('h1') articles = {i.a['href']: i.text.strip() for i in soup.findAll('h1') if i.a} for article in articles: s = '{title}: {url}'.format( title=articles[article], url=article) print(s) return articles if __name__ == '__main__': articles = get_articles()
Here we do our imports and set up what URL we are going to use. Then we create a function where the magic happens. We use the requests library to get the URL and then pull the HTML out as a string using the request object’s text property. Then we pass the HTML to BeautifulSoup which turns it into a nice object. After that, we ask BeautifulSoup to find all the instances of h1 and then use a dictionary comprehension to extract the title and URL. We then print that information to stdout and return the dictionary.
Let’s try to scrape another website. This time, we will look at Twitter and use my blog’s account: mousevspython. We will try to scrape what I have tweeted recently. You will need to follow the same steps as before by right-clicking on a tweet and inspecting it to figure out what we need to do. In this case, we need to look for the ‘li’ tag and the js-stream-item class. Let’s take a look:
import requests from bs4 import BeautifulSoup url = '' req = requests.get(url) html = req.text soup = BeautifulSoup(html, 'html.parser') tweets = soup.findAll('li', 'js-stream-item') for item in range(len(soup.find_all('p', 'TweetTextSize'))): tweet_text = tweets[item].get_text() print(tweet_text) dt = tweets[item].find('a', 'tweet-timestamp') print('This was tweeted on ' + dt)
As before, we use BeautifulSoup’s findAll command to grab all the instances that match our search criteria. Then we also look for the paragraph tag (i.e. ‘p’) and the TweetTextSize class and loop over the results. You will note that we used find_all here. Just so we’re clear, findAll is an alias of find_all, so they do the exact same thing. Anyway, we loop over those results and grab the tweet text and the tweet timestamp and print them out.
You would think that there might be an easier way to do this sort of thing and there is. Some websites provide a developer API that you can use to access their website’s data. Twitter has a nice one that requires a consumer key and a secret. We will actually be looking at how to use that API and a couple of others in the next chapter.
Let’s move on and learn how to write a spider!
Scrapy
Scrapy is a framework that you can use for crawling websites and extracting (i.e. scraping) data. It can also be used to extract data via a website’s API or as a general purpose web crawler. To install Scrapy, all you need is pip:
pip install scrapy
According to Scrapy’s documentation, you will also need lxml and OpenSSL installed. We are going to use Scrapy to do the same thing that we used BeautifulSoup for, which was scraping the title and link of the articles on my blog’s front page. To get started, all you need to do open up a terminal and change directories to the one that you want to store our project in. Then run the following command:
scrapy startproject blog_scraper
This will create a directory named blog_scraper in the current directory which will contain the following items:
- Another nested blog_scraper folder
- scrapy.cfg
Inside of the second blog_scraper folder is where the good stuff is:
- A spiders folder
- __init__.py
- items.py
- pipelines.py
- settings.py
We can go with the defaults for everything except items.py. So open up items.py in your favorite Python editor and add the following code:
import scrapy class BlogScraperItem(scrapy.Item): title = scrapy.Field() link = scrapy.Field()
What we are doing here is creating a class that models what it is that we want to capture, which in this case is a series of titles and links. This is kind of like SQLAlchemy’s model system in which we would create a model of a database. In Scrapy, we create a model of the data we want to scrape.
Next we need to create a spider, so change directories into the spiders directory and create a Python file there. Let’s just call it blog.py. Put the following code inside of your newly created file:
from scrapy.spider import BaseSpider from scrapy.selector import Selector from ..items import BlogScraperItem class MyBlogSpider(BaseSpider): name = 'mouse' start_urls = [''] def parse(self, response): selector = Selector(response) blog_titles = selector.xpath("//h1[@class='entry-title']") selections = [] for data in blog_titles: selection = BlogScraperItem() selection['title'] = data.xpath("a/text()").extract() selection['link'] = data.xpath("a/@href").extract() selections.append(selection) return selections
Here we just import the BaseSpider class and a Selector class. We also import our BlogScraperItem class that we created earlier. Then we subclass BaseSpider and name our spider mouse since the name of my blog is The Mouse Vs the Python. We also give it a start URL. Note that this is a list which means that you could give this spider multiple start URLs. The most important piece is our parse function. It will take the responses it gets from the website and parse them.
Scrapy supports using CSS expressions or XPath for selecting certain parts of an HTML document. This basically tells Scrapy what it is that we want to scrape. XPath is a bit harder to read, but it’s also the most powerful, so we’ll be using it for this example. To grab the titles, we can use Google Chrome’s Inspector tool to figure out that the titles are located inside an h1 tag with a class name of entry-title.
The selector returns a SelectorList instance that we can iterate over. This allows us to continue to make xpath queries on each item in this special list, so we can extract the title text and the link. We also create a new instance of our BlogScraperItem and insert the title and link that we extracted into that new object. Finally, we append our newly scraped data into a list which we return when we’re done.
To run this code, go back up to the top level folder which contained the nested blog_scraper folder and config file and run the following command:
scrapy crawl mouse
You will notice that we are telling Scrapy to crawl using the mouse spider that we created. This command will cause a lot of output to be printed to your screen. Fortunately, Scrapy supports exporting the data into various formats such as CSV, JSON and XML. Let’s export the data we scraped using the CSV format:
scrapy crawl mouse -o articles.csv -t csv
You will still see a lot of output generated to stdout, but the title and link will be saved to disk in a file called articles.csv.
Most crawlers are set up to follow links and crawl the entire website or a series of websites. The crawler in this website wasn’t created that way, but that would be a fun enhancement that you can add on your own.
Wrapping Up
Scraping data from the internet is challenging and fun. Python has many libraries that can make this chore quite easy. We learned about how we can use BeautifulSoup to scrape data from a blog and from Twitter. Then we learned about one of the most popular libraries for creating a web crawler/scraper in Python: Scrapy. We barely scratched the surface of what these libraries can do, so you are encouraged to spend some time reading their respective documentation for further details.
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The idea of this solution is from this page:,including nums with same value.
Thanks for this author about this brilliant idea. Here is my java solution
public class Solution {) factor2 = 2*ugly[++index2]; if(factor3 == min) factor3 = 3*ugly[++index3]; if(factor5 == min) factor5 = 5*ugly[++index5]; } return ugly[n-1]; } }
Thanks for sharing. I think the key here is as you mentioned, "including nums with same value.". factor2 and factor3 may both have value = 6, but we bump both "6"s together, thus the duplicated 6 won't cause any problem. I initially put it as "else if (factor3==min)", that fell to the trap :)
Your code is very concise.
I just modified it a little bit.
Since java program can keep some static members,
we can calculate all the ugly numbers that are less than or equal to Integer.MAX_VALUE and just store the result into a static array. After some trial, I found that, it is enough to get an array that have 1691 elements. (the 1691st ugly number is 2125764000 while the 1692nd one is 2147483648 which just overflow).
So for example, if we are asked what is the 1691st, 1690th, 1689th, 1688th, 1687th, .... ugly number, we will not need to calculate what we already know~ Just one round of calculation and all we need to do is to return the queried element in the array.
public class Solution { static int[] ugly = new int[1691]; static { ugly[0] = 1; int index2 = 0, index3 = 0, index5 = 0; int factor2 = 2, factor3 = 3, factor5 = 5; for (int i = 1; i < ugly.length; i++) { int min = Math.min(Math.min(factor2, factor3), factor5); ugly[i] = min; if (factor2 == min) factor2 = 2 * ugly[++index2]; if (factor3 == min) factor3 = 3 * ugly[++index3]; if (factor5 == min) factor5 = 5 * ugly[++index5]; } } public int nthUglyNumber(int n) { return ugly[n - 1]; } }
What if I only want the fifth ugly bum, however you calculate all 1691ugly nums. It might be useful under some specific conditions. But I think we should focus on algorithm here.
Yes, if we are asked what the 5th ugly number is, a lot of calculation is wasted.
But generally speaking, the test cases will be large enough.
By the way, I agree with you, the algorithm is the most important thing here.
Nice solution, it's very clever to find out every subsequence is ugly sequence itself multiply by 2, 3, 5.
i just write to thanks the person who made the post maybe others assume this should be an answer lol
Here is an more concise version:
public int nthUglyNumber(int n) { int[] nums = new int[n]; int index2 = 0, index3 = 0, index5 = 0; nums[0] = 1; for(int i = 1; i < nums.length; i++){ nums[i] = Math.min(nums[index2] * 2, Math.min(nums[index3] * 3, nums[index5] * 5)); if(nums[i] == nums[index2] * 2) index2++; if(nums[i] == nums[index3] * 3) index3++; if(nums[i] == nums[index5] * 5) index5++; } return nums[n - 1]; }
Golang solution:
func nthUglyNumber(n int) int { ugly:= make([]int, n) for k,_ := range ugly { ugly[k] = 0 } ugly[0] = 1; index2, index3, index5 := 0, 0, 0 factor2, factor3, factor5 := 2, 3, 5 for i:=1;i<n;i++ { min := min] } func min (a int, b int) int { if a > b { return b } else { return a } }
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* Greg KH <gregkh@suse.de>:> On Sat, Mar 01, 2008 at 07:43:07AM -0700, Matthew Wilcox wrote:> > On Fri, Feb 29, 2008 at 09:25:42PM -0800, Greg KH wrote:> > > What is the guarantee that the names of these slots are correctNo guarantee there. We report whatever firmware tells us.> > > and do not happen to be the same as the hotpluggable ones?Stronger guarantee here, since both pci_slot and <foo>hp driverwill be getting the name of the slot from the same place.> > That would be a bug -- and yes, bugs happen, and we have to deal with> > them.> > My main concern is that BIOS vendors will not fix these bugs, as no> other OS cares/does this kind of thing today. The ammount of bad> information out there might be quite large, and I think this was> confirmed by some initial testing of IBM systems, right?We saw problems on Fujitsu machines, where they return an errorcode when the _SUN method is called on a slot that exists in thenamespace but isn't actually present.After discussing with Kenji-san about specs, we came to theagreement that he was ok with this behavior because he had theoption to not load pci_slot on his machines.I agree that there might be lots of buggy firmwares out there,but we won't know for certain until we get some exposure. And Ithink the upside is worth it.Kristen suggested the linux-next tree. That sounds viable tome...> > > Why show this information on machines that can not do> > > anything with these slots at all? Will that not just> > > confuse people?> > > > Only for people who think that /sys/bus/pci/slots/ is for> > hotpluggable slots only. There is plenty of useful> > information available for slots that aren't hotpluggable (eg> > bus address, speed, width, error status).> > Can the userspace tools that are using the existing directories> thinking that only hotplug slots are there, handle> "non-hotplug" slots showing up in this location?Of course we shouldn't break userspace, no one wants that. Butnothing about that name (/sys/bus/pci/slots/) implies "hotplugonly", and we have no idea how big the problem might be.Again, I'm thinking more exposure in linux-next might be areasonable way for us to figure out how bad (or good) thesituation might really be out there.Thanks./ac | http://lkml.org/lkml/2008/3/4/487 | CC-MAIN-2017-04 | refinedweb | 392 | 71.85 |
Associative Data Modeling Demystified: Part IV
Associative Data Modeling Demystified: Part IV
In this article we will see how we can define an association in RDF and what are the differences with other data models that we analyzed in previous posts of our series.
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Introduction to RDF
In the previous post, part 3, of this series, we explored the Property Graph data model. It is now time to write about another Graph data model with a long history behind it, the Resource-Description-Framework (RDF). We will see how we can define an association in RDF and what the differences are with other data models that we analyzed in previous posts of our series.
RDF is a graph-based data model that has been designed to represent information as a labeled directed graph. In RDF, a description of a resource, i.e. any type of thing, is represented as a number of triples. Each triple has a subject, predicate, and object. Alternatively, if you want to think in terms of Entity-Relationship model, these three parts of the triple become the Entity-Attribute-Value. This is also known as the EAV model. For instance, the Entity subject
Part:998 of our Parts table in the example data set of our series can be serialized in Turtle syntax as:
Part:998 rdf:label "Fire Hydrant Cap"@en ; schema:color "Red"@en ; schema:weight "7.2"^^xsd:double ; schema:unitText "lb"@en ; dc:identifier "998"^^xsd:int .
These
rdf:label,
schema:color,
schema:weight,
schema:unitText,
dc:identifier are attributes of this Entity instance and “Fire Hydrant Cap”, “Red”, “7.2”, “lb” and “998” are atomic values with an accompanied data type, see also [Fig. 7].
RDF and Linked Data
But RDF is not like any other data model, it has been selected from W3C as one of the Web technologies, together with HTTP and URIs, to extend the hyperlinking of documents to a set of best practices for publishing and interlinking structured data on global scale. Today the term Linked Data refers to these standards, and the extension of the Web is also known as the Semantic Web. The predecessor of RDF, the Semantic Network Model, was formed in the early 1960s. The main difference is that arcs and nodes in RDF are identified using HTTP URIs and dereferenced (i.e., looked up) over the HTTP protocol. If we use N-Triples syntax to serialize the same resource
Part:998 we take:
<> <> "Fire Hydrant Cap"@en . <> <> "Red"@en . <> <> "7.2"^^<> . <> <> "lb"@en . <> <> "998"^^<> .
Notice that the
object part of the triple is an RDF literal and datatypes are used to represent values such as strings, numbers and dates. These triples are called Literal triples and describe the properties of resources. In our example, these
literal triples describe five properties of the
Part:998 resource. This type of RDF triples is distinguished from the other type which is RDF Links and describe the relationship between two resources. For example, if we want to express with the same syntax all the vendors of
Part:998 we will form these triples:
<> <> <> . <> <> <> . <> <> <> . <> <> <> .
This is also the equivalent result set at [Fig. 1] presented in a compact form from the following SPARQL query:
#Suppliers of Part 998 PREFIX Supplier: <> PREFIX Part: <> PREFIX xsd: <> PREFIX wd: <> PREFIX dc: <> select ?prt ?p ?sup where { BIND(wd:hasVendor AS ?p) # Start with a ?prt that has id=998 ?prt dc:identifier "998"^^xsd:int . # Find all catalog items (?cat) with a reference to ?prt ?cat wd:hasPart ?prt . # For any catalog item (?cat) find the vendor that supplies ?prt ?cat ?p ?sup . }
In [Fig. 1], the URI with QName
wd:hasVendor, in the
predicate position defines the type of relationship between a
subject with QName
Part:998 and an
object with any of these QNames (
Supplier:1081,
Supplier:1082,
Supplier:1083,
Supplier:1084). Both subject and object URIs are in the same namespace () — these are called Internal RDF links.
One way to think these RDF links is as a labeled directed graph. Each triple is a directed arc that connects a subject, e.g.
Part:998, with an object, e.g.
Supplier:1084, and the predicate is the label of the arc,
wd:hasVendor. For example, the previous result set can be represented with the following graph in [Fig. 2]:
But the graph for the data model of our example is slightly more complicated because there are intermediate nodes, i.e. inventory items that represent records from the Catalog table, that associate or bridge Suppliers with Parts [Fig. 3].
Another distinction of RDF links to Outgoing and Incoming can be seen in [Fig. 3]. For example,
Part:998 has four incoming RDF links of type
wd:hasPart, and
Item:7 has two outgoing RDF links of type
wd:hasPart and
wd:hasVendor , respectively.
In fact, the SPARQL query above has been written taking in consideration this graph. In order to traverse the nodes, you must know both the type of RDF link and its direction. In RDF graph data model edges are unidirectional. In order to define bidirectional edges, we have to define both outgoing and incoming RDF links for each node, i.e. two predicates [Fig. 4].
Association in RDF
We can now compare these five associations of
Part:998 with RDF links of the graph in [Fig. 6]. One of them is composed with all outgoing triples of
Part:998, i.e.
Part:998 is the subject of the triple [Fig. 5]. These
literal triples describe five properties of
Part:998 resource, yellow boxes of [Fig. 6], and another RDF link is for the type of resource, i.e.
Item(gray box).
# Get all outgoing triples for a specific part PREFIX Part: <> select ?prt ?p ?o where { BIND(Part:998 AS ?prt) ?prt ?p ?o . }
The resource
Part:998 participates in four associations with Inventory resources, as the object of a triple. These are the four incoming RDF links of
Part:998 in [Fig. 3], [Fig. 6], and [Fig. 8].
We can write the following SPARQL query to ask for all the suppliers of
Part:998, sorted by their catalog price.
#Suppliers of Part 998 (Red Fire Hydrant Cap) sorted by their catalog price PREFIX xsd: <> PREFIX wd: <> PREFIX schema: <> PREFIX rdf: <> PREFIX dc: <> select ?sup ?supName ?supCountry ?catPrice ?catQuantity ?prt ?prtName ?prtColor ?cat where { # Start with a ?prt that has id=998 get its name and color values ?prt dc:identifier "998"^^xsd:int . ?prt rdf:label ?prtName . ?prt schema:color ?prtColor . # Find all catalog items (?cat) with a reference to ?prt get their price and quantity values ?cat wd:hasPart ?prt . ?cat schema:cost ?catPrice OPTIONAL {?cat schema:quantity ?catQuantity .} # For any catalog item (?cat) find the vendor that supplies ?prt get their name and the country of origin ?cat wd:hasVendor ?sup . ?sup rdf:label ?supName . ?sup schema:country ?supCountry } ORDER BY ASC(?catPrice)
You may consider the analogy between this query and the result set at [Fig. 7] and the equivalent OrientDB SQL query and the result set from a Property Graph data model. The main differences are that in Property Graph data model you can traverse edges in both directions, (incoming, outcoming), the filtering part (
where) in SPARQL is significantly longer, and the starting point is represented in a different manner (edge vs link).
We can view a graph representation, [Fig. 8], of this SPARQL query and its result data set [Fig. 7]. In the same screen capture, [Fig. 8], a many-to-many relationship is modeled with RDF triples.
Supplier:1082 is associated with three parts (
Part:991,
Part:997 and
Part:998) and
Part998 is associated with four suppliers (
Supplier:1081,
Supplier:1082,
Supplier:1083, and
Supplier:1084), see also [Fig. 9]. From a semantic point of view, Parts and Suppliers participate in associations with Inventory items (green boxes —
Catalog:7,
Catalog:9,
Catalog:10,
Catalog:11,
Catalog:12 , and
Catalog:16). In contrast with the binary relations between Suppliers and Parts represented with directed edges in a Property Graph, see here, instead of an edge type, we have explicit intermediate (bridge) nodes and instead of outgoing head (out) and incoming tail (in) we have two outgoing directional links (
wd:hasPart and
wd:hasVendor) from this intermediate node, e.g. Catalog/Inventory item to Supplier and Part. In such as case these outgoing directional links (
wd:hasPart and
wd:hasVendor) look like roles in a Topic Map binary association.
/* 4 Associations of catalog part no 998 with supplier Ids and catalog prices */ Catalog07( Part998:HasPart, Supplier1081:HasVendor, 11.7:Cost ) Catalog11( Part998:HasPart, Supplier1082:HasVendor, 7.95:Cost ) Catalog12( Part998:HasPart, Supplier1083:HasVendor, 12.5:Cost ) Catalog16( Part998:HasPart, Supplier1084:HasVendor, 48.6:Cost )
Associative Model
Although it has not become mainstream, we see the associative model of data as an effort to enhance RDF data model in a new kind of DBMS. The logical layer of Sentences associative database management system may be regarded as comprising of only two tables: one for
Items that represent
Entities,
Entity Types,
Values, and
Value Types and one for
Links that represent among other things
Associations and
Association Types.
Both
Items and
Links also represent meta-types and instances, which perform various functions in the database ([Fig. 15], [Fig. 16]). Thanks to this simple consistent form of
Items and
Links, it is easy to write generic code that is capable of working with every type of data. Recording schema changes and transactions, a type system [Fig. 15], associative queries in the form of a request tree, business rules, data provenance, automated default data entry forms [Fig. 16], and many other features of Sentences DBMS were designed and implemented based on this generic metacode programming.
Fig. 16: Types, Entity Instances, and Data Entry Forms
In fact, along similar principles, the Freebase collaborative knowledge base, now known as Google’s Knowledge Graph, was serving its users.
Both Freebase and Sentences also added reverse edges to their model. In Freebase notation, [Fig. 10] we can see that
/film/film is
/directed_by a
/film/director and a
/film/director has directed (
/film) a
/film/film.
Bidirectional links allow a 360° view of every data item in the database. Directed edges in Property Graph share the same concept, see here. In the following three figures (Fig. 11, Fig. 12, Fig. 13), we present three alternative schema views for our Supplier-Part-Catalog database that we built on the Sentences DBMS. Fig. 11 illustrates that it is possible to add attributes on the link. Fig. 12 shows that the
Supplier,
Catalog, and
Part entities are sharing common attributes, while in Fig. 13, they are directly connected with bidirectional links.
Association in R3DM
According to R3DM Hypergaph Terminology, the objects of
RDF literal triples, i.e. values, are HyperAtoms and the resources of RDF links, are HyperBonds. Thus the RDF graph of [Fig. 8] can be redrawn as a hypergraph with red nodes that play the role of HyperAtoms, and green nodes that play the role of HyperBonds, see [Fig. 14].
This R3DM hypergraph figure above, [Fig. 14], has been created from the execution of the following Wolfram Language code. You will notice that HyperAtom sets, such as ha2-(catcost) and ha5-(catqnt), are attribute sets with value members that take part in the formation of Catalog records with instances that are drawn from hb2 set and ha3-(sname) and ha4-(scountry) are attribute sets with value members that describe the Suppliers of hb3 set.
Instances from these HyperBond sets may share common values or associated with the same HyperBond. For example, we have two suppliers, Supplier:1082 and Supplier:1081 that are located in USA or Catalog:11 and Catalog:16 entries that are associated with Part:998, and they both have the same quantity, i.e. 200 pieces of this part.
ha1={998,"Fire Hydrant Cap","Red",7.2`,"lb"}; ha2={11.7,7.95,12.5,48.6}; ha3={"Acme Widget Suppliers","Big Red Tool and Die","Perfunctory Parts","Alien Aircaft Inc."}; ha4={"USA","USA","SPAIN","UK"}; ha5={"400","200","200"}; hb1={"Part:998","schema:item"}; hb2={"Catalog:7","Catalog:11","Catalog:12","Catalog:16"}; hb3={"Supplier:1081","Supplier:1082","Supplier:1083","Supplier:1084"}; vstyle=Join[Thread[Join[ha1,ha2, ha3,ha4,ha5]->Red],Thread[Join[hb1,hb2,hb3]->Green]]; data=Join[ {"Part:998"->"schema:item"}, Thread["Part:998"->ha1],Thread[hb2->ha2], Thread[hb2->hb3],Thread[hb3->ha3], Thread[hb3->ha4],Thread[hb2->"Part:998"], Thread[{"Catalog:7","Catalog:11","Catalog:16"}->ha5]]; Graph[ data, VertexLabels->"Name", VertexSize->Nearest, VertexStyle->vstyle, EdgeShapeFunction->GraphElementData[{"CarvedArrow","ArrowSize"->.02}], EdgeStyle->Thick, GraphLayout->"SpringEmbedding", ImageSize->{400.,Automatic} ]
We can now rewrite the following four associations:
/* 4 Associations of catalog part no 998 with supplier Ids and catalog prices */ CatalogID( catpid, catsid, catqnt, catcost) Catalog07( Part998, Supplier1081, 400, 11.70 ) Catalog11( Part998, Supplier1082, 200, 7.95 ) Catalog12( Part998, Supplier1083, 12.50 ) Catalog16( Part998, Supplier1084, 200, 48.60 )
Associations in this form greatly resemble tuples of Catalog relation, see TSV format, where the heading of this relation is usually stored in a data dictionary and Null marker indicates that a data value is absent from the tuple. On the contrary in case of RDF literal triples the predicate position signifies the object part of the triple and in RDF links Instances/Type of resources at subject and object positions are also signified by predicates such as (
rdf:type). But in R3DM associations there is not any label on the edge that connectsHyperAtoms or HyperBonds. Therefore the denotation of resources and literals, i.e. what they stand for, cannot be seen on this graph, [Fig. 14]. For example in
Catalog12 association instance we have to know that the literal meaning of the value
12.5 is the Catalog Cost. Generally speaking, this is the granularity of data problem. How we represent a piece of information at atomic level and how we construct higher structures. R3DM/S3DM unifies three perspectives, semantics at the conceptual layer, representation at the symbol layer and encoding at the physical layer, in such a way that they are separable. R3DM/S3DM conceptual framework is based on the natural process of semiosis where the signified, i.e. concept, entity, attribute and the signifier, i.e. value, are referenced through symbols, i.e. signs, at discrete layers. The main difference with RDF data model is that these references are not in the form of URIs but they resemble IPs. For example, the value
12.50 can be referenced by a 4D vector of the form
{2, 8, 262, 1}, where the first dimension is the database, the second dimension is the table (Entity), the third dimension is the field (Attribute) and the last dimension is a member of an attribute set.
Discussion
Although this is not the space or the time to elaborate more on R3DM/S3DM associations, it is important to mention that it is possible to escape from the predicate logic (
owl#sameAs) on how to identify that two URI aliases refer to the same entity. Moreover the alternative paradigm of R3DM/S3DM offers a more attractive and efficient approach on data integration and heterogeneous data representation than bridging between RDF vocabularies with mapping predicates such as
owl:equivalentClass and
owl:equivalentProperty.
We foresee that the Internet of things will use a protocol with numerical reference vectors for data communication in a similar fashion to IP addresses that are used for connecting devices in a computer network. Hopefully one day it will become clear that the predicate part of RDF data model is causing more harm than good in the semantic interpretation and information representation.
Last but not least, SPARQL query mechanism is heavily dependent on namespace vocabulary terms, especially predicate terms that connect resources and literals. To answer such queries, care must be taken to devise a suitable mechanism of indexes (e.g. spo, sop, pso, pos, osp, ops) to support RDF triple structure. Besides indexing, RDF edges by default are not bidirectional, therefore 360 degrees view and nodes navigation is problematic. In contrast with RDF, in R3DM/S3DM everything is bidirectionally linked and referenced with 4D numerical vectors and these are naturally used for indexing purposes. Instead of writing queries there is a functional way, i.e. you learn a single command with a standard number of optional or mandatory parameters, to filter the data space and retrieve any piece of information.
Interactive and associative data exploration is the key, unique feature of Qlikview/Qliksense, one of the best data visualization and business intelligence software in the market today. Behind the scenes, columnar, binary indexing capability is the foundation for QIX Associative Data Indexing Engine. In the next part of our series we will apply Qlik associative technology on our toy dataset and we will demonstrate how we build the domain model and how we filter our data.
Acknowledgements
We have serialized our Supplier-Part-Catalogue example in Turtle and N-Triples syntax. Then we used AllegroGraph and GraphDB triple-store to create a repository and run queries on their SPARQL interfaces. All graph-based images of this article were displayed and captured on Gruff, an RDF visual browser that displays a variety of the relationships in AllegroGraph.
Opinions expressed by DZone contributors are their own.
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Hi all,
I am unable to start a new silverlight business application in visual studio 2010. It is giving the error as
"The type or namespace name 'Resources' does not exists in the namespace 'BusinessApplication1.Web' (are you missing an assembly reference')
can anyone help to rectify this error
Please try to repair silverlight ria service and install Ria Serivce toolkit from below link
Microsoft is conducting an online survey to understand your opinion of the Msdn Web site. If you choose to participate, the online survey will be presented to you when you leave the Msdn Web site.
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ASN1_TYPE_get, ASN1_TYPE_set, ASN1_TYPE_set1, ASN1_TYPE_cmp, ASN1_TYPE_unpack_sequence, ASN1_TYPE_pack_sequence - ASN1_TYPE utility functions
#include <openssl/asn1.h> int ASN1_TYPE_get(const ASN1_TYPE *a); void ASN1_TYPE_set(ASN1_TYPE *a, int type, void *value); int ASN1_TYPE_set1(ASN1_TYPE *a, int type, const void *value); int ASN1_TYPE_cmp(const ASN1_TYPE *a, const ASN1_TYPE *b); void *ASN1_TYPE_unpack_sequence(const ASN1_ITEM *it, const ASN1_TYPE *t); ASN1_TYPE *ASN1_TYPE_pack_sequence(const ASN1_ITEM *it, void *s, ASN1_TYPE **t);
These functions allow an ASN1_TYPE structure to be manipulated. The ASN1_TYPE structure can contain any ASN.1 type or constructed type such as a SEQUENCE: it is effectively equivalent to the ASN.1 ANY type.
ASN1_TYPE_get() returns the type of a.
ASN1_TYPE_set() sets the value of a to type and value. This function uses the pointer value internally so it must not be freed up after the call.
ASN1_TYPE_set1() sets the value of a to type a copy of value.
ASN1_TYPE_cmp() compares ASN.1 types a and b and returns 0 if they are identical and non-zero otherwise.
ASN1_TYPE_unpack_sequence() attempts to parse the SEQUENCE present in t using the ASN.1 structure it. If successful it returns a pointer to the ASN.1 structure corresponding to it which must be freed by the caller. If it fails it return NULL.
ASN1_TYPE_pack_sequence() attempts to encode the ASN.1 structure s corresponding to it into an ASN1_TYPE. If successful the encoded ASN1_TYPE is returned. If t and *t are not NULL the encoded type is written to t overwriting any existing data. If t is not NULL but *t is NULL the returned ASN1_TYPE is written to *t.
The type and meaning of the value parameter for ASN1_TYPE_set() and ASN1_TYPE_set1() is determined by the type parameter. If type is V_ASN1_NULL value is ignored. If type is V_ASN1_BOOLEAN then the boolean is set to TRUE if value is not NULL. If type is V_ASN1_OBJECT then value is an ASN1_OBJECT structure. Otherwise type is and ASN1_STRING structure. If type corresponds to a primitive type (or a string type) then the contents of the ASN1_STRING contain the content octets of the type. If type corresponds to a constructed type or a tagged type (V_ASN1_SEQUENCE, V_ASN1_SET or V_ASN1_OTHER) then the ASN1_STRING contains the entire ASN.1 encoding verbatim (including tag and length octets).
ASN1_TYPE_cmp() may not return zero if two types are equivalent but have different encodings. For example the single content octet of the boolean TRUE value under BER can have any non-zero encoding but ASN1_TYPE_cmp() will only return zero if the values are the same.
If either or both of the parameters passed to ASN1_TYPE_cmp() is NULL the return value is non-zero. Technically if both parameters are NULL the two types could be absent OPTIONAL fields and so should match, however passing NULL values could also indicate a programming error (for example an unparseable type which returns NULL ) for types which do not match. So applications should handle the case of two absent values separately.
ASN1_TYPE_get() returns the type of the ASN1_TYPE argument.
ASN1_TYPE_set() does not return a value.
ASN1_TYPE_set1() returns 1 for success and 0 for failure.
ASN1_TYPE_cmp() returns 0 if the types are identical and non-zero otherwise.
ASN1_TYPE_unpack_sequence() returns a pointer to an ASN.1 structure or NULL on failure.
ASN1_TYPE_pack_sequence() return an ASN1_TYPE structure if it succeeds or NULL on failure.
Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <>. | https://www.zanteres.com/manpages/ASN1_TYPE_set.3ssl.html | CC-MAIN-2022-33 | refinedweb | 578 | 50.12 |
Pushing the new stuff
This week we released an updated Silverlight Toolkit - the Silverlight Toolkit March 2009 release. This release has some new components, but we spent a lot of time working to make sure that the Toolkit can be updated in an agile way, but still fits in nicely with other platform and tools releases.
The main thing that we wanted to establish was a smooth flow of components from the Toolkit into the platform, in this case the SDK. Most Toolkit components are things that people will want to have in their default tooling experience, and one of our goals is to minimize the number of things that developers must download to get productive with the platform. So the first order of business was to setup the Toolkit to be primarily an incubation vehicle for SDK components. So most components start in the Toolkit, and end up eventually in the SDK that comes with Visual Studio or Expression Blend.
This also meant pulling the existing SDK controls into the Toolkit package. With the March 2009 release, you'll find the source code for all of the Silverlight 3 versions of the SDK controls - DataGrid, Calendar, TabControl, etc. As with the rest of the Toolkit, this code is licensed under MS-PL so you're free to modify it or use it in your application.
With Silverlight 3 coming into the picture, we needed to structure the Toolkit project to be able to handle both versions. Our philosophy is to do as much work in the Silverlight 2 Toolkit as possible, then just do things in Silverlight 3 that have a dependency on the new runtime. We'll continue to support Silverlight 2 up through the release of Silverlight 3, then we'll focus on Silverlight 3 exclusively as customers upgrade. On the Release page you'll see a Silverlight 3 Beta and Silverlight 2 installer.
I've always been a big believer in delivering great design-time experiences. We've done a lot of work with the tools teams to make sure that our components work well with the designers, including having items in the Toolbox and having the right properties show up in the tool. This turned out to be more work than we had anticipated and we're hopeful that any customers that are writing components can use what we've done as a good example of how to make all of this stuff work. We'll keep pushing on making this a great experience over time.
The biggest piece of feedback we've gotten is to have our Samples available in VB.NET as well as C#, so we did the work to make that happen.
In addition, we've fixed the highest-voted bugs in components across the Toolkit including Charting, AutoCompleteBox, and TreeView. Thanks to everyone that took the time to file issues or vote, that data is very helpful to us. One catch here is that some of our components (like TreeView) need to maintain API compat with WPF, so that limits the type of changes that we can make.
We also now have an MSI-based installer package that installs the Toolkit for you and gets the Toolkit control items into the Visual Studio Toolbox or Blend Asset Panel automatically. This helps with the discovery of components and makes them easier to add to your projects. It also sets up a nice Start Menu entry as well:
We've also added some new controls - Accordion, DomainUpDown, and TimePicker, all of which are in the Preview band for this release. Check them out!
If you're upgrading from a prior version of the Toolkit, you'll notice that the namespace names for most components have changed from Microsoft.* to System.*. So for this upgrade, you'll need to go through the process of updating your code, so sorry for that up front.
This was something we spent a *lot* of time talking through. The original reason for making the Toolkit components be in Microsoft was so that we could add components to the SDK or the Core and not have them conflict with Toolkit versions. We wanted there to be an opt-in change when developers moved from a Toolkit control to the platform version - we'd delay the need for the user to make a change until the very end. But the user would need to update source code. The more we thought about this, and talked to customers, the more it seemed like this wasn't the right thing to do since it means more-and-more code that you'll need to fix up if you wait longer. Instead, for the components we expected to make it into the platform, it was better to put them into their final namespace and then physically move them into the platform assembly when they were fully mature. This meant having a new Toolkit build with each platform release that has those types removed. But that's something we do anyway, and doing it this way means that customers only need to update their references and maybe their XAML xml namespace, and that's it. Code should continue to run. We decided that was a better model.
In conjunction with that, we needed to make sure that installing or using the Toolkit was something that didn't disturb the supported platform release. So that meant Toolkit assemblies had to be able to sit side-by-side with SDK assemblies. To accomplish that, we appended the word "Toolkit" to the Toolkit assemblies and that makes an easy mapping for where things are in the Toolkit to where they will end up in the SDK.
Here is an example:
Today, System.Windows.Controls.Accordion is in System.Windows.Controls.Layout.Toolkit.dll. Someday in the future, Accordion will reach the Mature Quality Band and then a platform release will happen and it will be moved into the SDK. When the next version of Silverlight ships, we will ship a corresponding Toolkit and SDK. The Accordion component will move into System.Windows.Controls.Layout.DLL (note no "Toolkit" in there), which is part of the SDK itself. Developers using this component will need to add a reference to that SDK assembly and (optionally) remove the reference to System.Windows.Controls.Layout.Toolkit.dll if it's not needed anymore. The developer would also need to update their XML namespace definition to point to the SDK version of the DLL so that the XAML parser knows where to find it. That should be it, and the project will now be using the SDK version of the component with no code changes.
What this unfortunately means is that we've got quite a few assemblies coming out of the Toolkit. We've tried to intelligently bucket the Toolkit controls into a few different assemblies so you don't have to pay to have a bunch of components in your XAP you're not using. We'll do the same thing for the SDK. But given the above, you get 2 assemblies for each bucket. Unfortunately, that's the simplest solution even if it's a little verbose.
As I mentioned above, the full source for the SDK components is now present in the Toolkit project. The Toolkit only includes source for these components, not the components themselves. Many parts of the system (for example Blend) are tested and built against the released version of the SDK components. We don't want the Toolkit updating these by default, but we do want to allow developers to make fixes to these components and deploy them with their applications if needed. In the Toolkit you'll find a Toolkit solution and an SDK solution so there is a nice separation there. If you do make a change to one of these components, you can just update the reference in your project to your rebuilt version and run against that.
The Toolkit also includes two great new themes: Bubble Cream and Twilight Blue.
We've added AreaSeries in the Charts
Looking forward to hearing your feedback!
The majority of the controls in the Silverlight Toolkit November 2008 (PDC) release are Silverlight versions of controls already present in WPF.
These "WPF Parity" controls include:
We focused heavily on API compatibility for these controls, only making changes (I'm actually not sure if there were any) for things that aren't currently possible on the Silverlight 2 runtime. And some things, like supporting Visual State Manager, required internal changes that made the process more complicated than just copying the existing WPF code.
We did leverage the WPF control specs and use the WPF controls behavior as our guidelines, and we were pretty hard-core about making sure the Silverlight Toolkit control's API was a strict subset of the corresponding WPF control's API. One of the primary compatibility goals was also to enable sharing of design assets, via VSM between WPF and Silverlight with minimal changes, and this enables that as well.
Even so, the controls aren't "strictly" compatible for two main reasons:
The upshot of all of this is that, to move your code from Silverlight to WPF, for the "parity" controls listed above, you'll need to do two things:
The constraints outlined above made it difficult to make compat "Just Work" at this point in time. Doing so would have required a set of complex tooling changes and too many "moving parts" that could result in broken applications or versioning issues. As such, our main goal was to make this compatibility experience simple, consistent, understandable, and something the compiler can help you with. All of which tend to be my preferences in most cases. It's much easier for us to implement and deliver, while being easy for developers to manage. At some point we may add some help to automate this if developers do have trouble with it.
Which brings me to the point of all of this.
Looking at the CodePlex IssueTracker, there are quite a few issues reported that are more feature requests than bugs. Unfortunately, many of these are things that we can't do without affecting the "subset" compat that I mentioned below.
For example, there are several of these relating to the the TreeView:
TreeView: Ability to Cancel TreeViewItem Selection
TreeView: Showing Connecting Lines in TreeView
We are having some conversations about how to handle this. The optimal solution would be for us to be able to have a derived TreeView class that does all this stuff, that we can then port back over to WPF so the same "extended" functionality works there. Another option would be to write a separate "TreeViewEx" that does this, but that brings with it the potential for a lot of confusion and duplication. And in both cases, we're investigating how many of these modifications can coexist peacefully. We're still investigating.
In any case, this is an area where we're happy to take feedback on or any other ideas about how best to handle this.
* when controls move from the Toolkit such that a control exists in both places for some amount of time you may need to do an explicit "using DockPanel = System.Windows.Controls.DockPanel;" disambiguation.
The!.
Just.!.
One of the things I was most excited about when we shipped the Silverlight 2 Beta 1 controls was the included unit testing harness, written by Jeff Wilcox. I think it's a good thing when we can share some of our internal tooling. It's good for customers, because they can leverage the work that we've been doing, and it's good for people here because it gives them a chance to "ship" something and get some visibility in the industry. And this is definitely the case with the Silverlight Unit Test Framework, which Jeff has just updated for RC0.
This is the exact package that we're using internally to run our automated unit tests and we've been adding features to it as our team grows. Oftentimes, development teams here at Microsoft use a different testing harness from what the testing teams use (please don't ask...) and I'm keen to avoid that setup, and the Silverlight Unit Test Framework provides the functionality for both. And that we're allowing customers to leverage it opens up some other possibilities that I'll get into later. Note that the Silverlight Unit Test Framework is an unsupported toolset, not an official Microsoft product.
Some of you may be asking why we wrote our own unit testing harness instead of using something like nUnit or MbUnit. The main reason is because the existing offerings were all written against the full .NET Framework. Even though Silverlight is .NET code, it really is a different platform. And it has some special needs due to the constraints on the type of reflection you can use (public only) and how you're able to instantiate and discover tests. So we decided we needed a harness that was written fully in Silverlight and hosted the tests directly in the harness itself. This has worked out well.
So if you're starting to get rolling with Silverlight, and you want to do some unit testing, definitely give the Silverlight Unit Test Framework a look.
More details here.).
Yes,!
I)
{);
}
_openAnimation = _rootElement.Resources[ExpandoHeaderControl.OpenAnimation] as Storyboard;
_closeAnimation = _rootElement.Resources[ExpandoHeaderControl.CloseAnimation] as Storyboard;
}
ChangeVisualState();
_templateLoaded = true;
}();
}
Beta 2:);
}.
If
[UPDATE:! | http://blogs.msdn.com/sburke/default.aspx | crawl-002 | refinedweb | 2,251 | 59.23 |
Agenda
See also: IRC log
->
Accepted.
->
Accepted.
No regrets heard.
ACTION-2009-01-29-01 completed
Mohamed: I didn't see very much
in common between our specs. They're mostly using binary
offsets.
... There are a few others that go inside ZIP to check for files.
Norm: So you didn't see anything that seemed out of the ordinary?
Mohamed: They're using some new
space characters and they're doing a case-insensitive
comparison in some places.
... I'll be watching those things.
Norm: It doesn't sound like there's anything we as a WG need to comment on.
Mohamed: I don't think so.
ACTION-2009-01-29-02 continued
->
Norm: This is about attempts to redefine steps in the p: namespace.
Vojtech: I thought err:XS0036 would cover it.
Norm: Yes, but I think we also want the error to cover the case of declaring p:foo
Vojtech: Ok, then we don't have an error for that.
Norm: I think we should just create a new error for this, any objections?
None heard.
->
This is about the term "document sequence". Should we define it?
Norm: I've never thought we meant more or less than what the English language words mean.
Vojtech: If we have a formal
definition of sequence, then we'd need to define other
things.
... The word sequence is almost the definition.
Alex: Since the term sequence in
XQuery/XPath 2 has a particular concept, perhaps we need a
definition is looser.
... XPath 2 has a bunch of loaded semantics that we don't want to inherit.
Norm: True, you never get an XPath 2.0 "sequence" from our "sequence of documents".
Some discussion about the fact that you can't actually access our sequences as a XPath 2.0 sequence.
Norm: Does anyone think we need to try to tie this down?
Henry: I think it's likely to be harder to get right than to say nothing about it. It's very hard to get right.
Mohamed: Especially if you want to have room to do parallel optimization.
Vojtech: In XQuery (and XSLT) we do say that the sequence becomes the default collection.
Norm: But that's a collection not
a sequence.
... I propose that we close this with no action.
Accepted.
->
Norm: The request here is that we support the 'text' serialization method.
Alex: I think this is a quality-of-implementation issue. There's nothing that prevents implementations from doing more.
Mohamed: I agree. I think XML serialization is the bare minimum. Getting text right is actually quite hard.
Norm: Anyone want to argue for including more than XML as mandatory?
None heard.
Norm: I propose that we decline and leave other methods as implementation-defined.
Accepted.
->
Norm attempts to summarize.
Norm: I just don't know if useful headers can be associated with a body.
Vojtech: I think the body can have arbitrary headers. That's what the text of the step says.
Alex: I think you're right.
Norm: That makes me want to put a wrapper around each collection of (header*,body), but maybe it's too late for that.
Alex: There's more work that you have to do to encode the pieces.
Norm: I just wish we had c:part wrappers around them, but I don't think we can do that now.
Vojtech: We don't handle nested multipart bodies either.
Norm: So I guess the proposal is to fix the grammar so that it allows a mixture of headers and bodies.
Accepted.
->
Norm attempts to summarize.
Norm: I think the intent was to flip the 2nd and 3rd paras of 7.1.10.4 and make the "translation of the text into a Unicode character sequence" only apply to non-XML media types.
Mohamed: I think that was the intent.
Alex: The intersection between
these two paragraphs is not zero.
... If you have an XML media type or a text type, then you can make a sequence of characters. If it's an XML media type, then you should parse it.
Norm: So this is intended to be two-part process.
Alex: Maybe the right thing to do
here is leave most of that first sentence and just at the end
say that you're supposed to construct a sequence of
characters.
... Make the part about making a c:body a separate part.
Norm: What I hear is that the
intent is to get Unicode characters first, then parse them if
it's an XML media type.
... Anyone disagree?
None heard.
Norm: I propose we get our editor to fix this.
Accepted.
->
Norm: This is about what should happen if you hand a random XML document to a processor.
Vojtech: I think it should be separate static error.
Norm: My concern is: should we mandate the behavior or say that it's implementation defined.
Mohamed: Use XPointer if you want to embed pipelines.
Vojtech: Importing would be a problem too.
Norm: I think the proposal is make it a new static error if the pipeline document doesn't have a root of p:pipeline, p:declare-step, or p:library.
Mohamed: yep.
Accepted.
->
Norm: I think some examples would
be useful, perhaps in a non-normative appendix.
... Does anyone else think that would be valuable?
Vojtech: I have problems with understanding all the details.
Mohamed: If you have explicit connections, why do you have to reorder them?
Norm: Only so that you can get the execution order right.
Mohamed: I think reorder and
execution order are different things.
... I'm trying to find out why we're trying to make the process harder than necessary.
Vojtech: So is there a use case for writing the steps out of order?
Mohamed: Only to make authoring easier.
Some discussion of how to achieve the order.
Norm: Make the implicit connections explicit, then look for cycles. If you find a cycle, the author loses. If you don't, then pick one of the partial orders and you're good to go.
Vojtech: Ok, I'm satisfied for now.
Norm: In that case, I think we should just close this without action.
Accepted.
None heard.
Adjourned | http://www.w3.org/XML/XProc/2009/02/05-minutes | CC-MAIN-2014-41 | refinedweb | 1,032 | 76.42 |
This C Program implements linear search. Linear search is also called as sequential search. Linear search is a method for finding a particular value in a list, that consists of checking every one of its elements, one at a time and in sequence, until the desired one is found.
Here is source code of the C program to implement linear search. The C program is successfully compiled and run on a Linux system. The program output is also shown below.
/*
* C program to input N numbers and store them in an array.
* Do a linear search for a given key and report success
* or failure.
*/
#include <stdio.h>
void main()
{
int array[10];
int i, num, keynum, found = 0;
printf("Enter the value of num \n");
scanf("%d", &num);
printf("Enter the elements one by one \n");
for (i = 0; i < num; i++)
{
scanf("%d", &array[i]);
}
printf("Input array is \n");
for (i = 0; i < num; i++)
{
printf("%dn", array[i]);
}
printf("Enter the element to be searched \n");
scanf("%d", &keynum);
/* Linear search begins */
for (i = 0; i < num ; i++)
{
if (keynum == array[i] )
{
found = 1;
break;
}
}
if (found == 1)
printf("Element is present in the array\n");
else
printf("Element is not present in the array\n");
}
$ cc pgm20.c $ a.out Enter the value of num 5 Enter the elements one by one 456 78 90 40 100 Input array is 456 78 90 40 100 Enter the element to be searched 70 Element is not present in the array $ a.out Enter the value of num 7 Enter the elements one by one 45 56 89 56 90 23 10 Input array is 45 56 89 56 90 23 10 Enter the element to be searched 45 Element is present in the array
Sanfoundry Global Education & Learning Series – 1000 C Programs.
Here’s the list of Best Reference Books in C Programming, Data-Structures and Algorithms
If you wish to look at other example programs on Searching and Sorting, go to C Programming Examples on Searching and Sorting. If you wish to look at programming examples on all topics, go to C Programming Examples. | https://www.sanfoundry.com/c-program-linear-search/ | CC-MAIN-2018-30 | refinedweb | 359 | 62.11 |
In this Quick Tip, we'll create a static, re-usable ActionScript class that will produce a Typewriter effect with a single line. Read on!
Step 1: Brief Overview
We'll split a user defined string into an array, and then add the resulting letters to a
TextField one by one using the
Timer class.
Step 2: Typewriter Class
Our class will be
static, which means it doesn't need to be instantiated using the
new keyword. To access a static class member, use the name of the class instead of the name of an instance.
Create a new ActionScript file and write the following code:
package { import flash.text.TextField; import flash.utils.Timer; import flash.events.TimerEvent; public final class Typewriter { /* Declare the variables and methods as static */ private static var chars:Array; //the characters in the string private static var tf:TextField; //textfield to which the string will be written private static var timer:Timer; //pauses between writing each character private static var i:int = 0; //variable used to count the written characters public static function write(txt:String, txtField:TextField, time:Number):void { chars = txt.split(""); //split the string into an array of characters tf = txtField; //assign tf to the text field passed to the function timer = new Timer(time); //set time according to parameter timer.addEventListener(TimerEvent.TIMER, writeChar); timer.start(); //start writing function } private static function writeChar(e:TimerEvent):void { if (i < chars.length) { tf.appendText(chars[i]); //writes a char every time the function is called i++; //next char } if (i >= chars.length) //check whether string is complete { timer.stop(); timer.removeEventListener(TimerEvent.TIMER, writeChar); //clear timer timer = null; } } } }
Step 3: Usage
The usage couldn't be easier - just add the
Typewriter.as class to your project folder and use the following code:
import Typewriter; Typewriter.write('Text to Write', targetTextfield, 50);
That's it, test your movie and you'll see your TextField using the Typewriter effect.
Step 4: Example
I used the class in on this example swf so you can see the effect:
Conclusion
Use this class to create your own effects!
Thank you for reading. If you'd like a more advanced version of this effect for use in your projects, take a look at Rasmus Wriedt Larsen's Letter By Letter Animation.
Envato Tuts+ tutorials are translated into other languages by our community members—you can be involved too!Translate this post
| https://code.tutsplus.com/tutorials/quick-tip-create-a-typewriter-text-effect-class--active-10917 | CC-MAIN-2016-50 | refinedweb | 404 | 62.68 |
Results 1 to 8 of 8
Thread: compiler problem
- Join Date
- Dec 2005
- 22
compiler problem
#include <iostream.h>
int main(int argc, char **argv)
{
cout << "Hello World";
return 0;
}
and I get the following error message
[wiraj@x1-6-00-09-6b-40-03-e7 Qt]$ g++ hello1.cpp
In file included from /usr/lib/gcc/i586-mandrake-linux-gnu/3.4.1/../../../../include/c++/3.4.1/backward/iostream.h:31,
from hello1.cpp:1:
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.1/../../../../include/c++/3.4.
A final note I am not sure if this is related or not but I have been having trouble compiling binaries downloaded as tar.gz files in my system. The make utility points me to some strange syntax errors in the code I am using gcc version 3.4.1 with mandrake 10.1
- Join Date
- Dec 2005
- 22
Oh that's a useful answer, please guys just tell me what's wrong with this. what am I doing wrong
Originally Posted by wirajR
The problem with your code is that you are using <iostream.h>, which is a deprecated header file. Instead, you should use #include <iostream>.
As you note, you get an error. Had you read the link that you were given, you would have noticed the line "using namespace std".
#include <iostream> gives access to cout, cin, and endl, all of which are in the "std" namespace. You may either incorporate the entire std namespace into your own program ("using namespace std"), or you may invoke each of these by their full name ("std::cout", "std::cin", "std::endl").
- Join Date
- Dec 2005
- 22
Oh thank you very much sir. I totally missed the link above, I am new to these forums and not used to the way it works .
- I totally missed the link above...
This thread is a perfect case in point: fingal posts a good answer, but it appears (because of the way links appear here) that he is telling the OP to read his signature, which of course makes no sense in this context.
I would actually recomend programming in the C language instead of C++, as C++ is a lot harder
- Join Date
- Dec 2005
- 22
Thanks for your advice but I am more comfortable with OO. I am a Java programmer with 5 years experience and using only C would deny me most of the Java like features I am used to. | http://www.linuxforums.org/forum/newbie/52636-compiler-problem.html | CC-MAIN-2018-13 | refinedweb | 412 | 71.85 |
Opened 6 years ago
Closed 6 years ago by
comment:2 Changed 6 years ago by
comment:3 Changed 6 years ago by
By the way, thanks for the report, you've come to the right place. It's always useful to get feedback from new users on how to improve the documentation.
comment:4 Changed 6 years ago by
Jumped in and created a patch for this.
- Reshuffles the sections to better show how the widgets are used.
- Brushed up some internal references and removed faulty docs (relating to the format on date and time widgets)
- Added an example and explanation about choices.
comment:5 Changed 6 years ago bygets displayed and to make it more digestible.
- Add double back-quotes around
yearsin "the years attribute is set..." (or use an :attr: clause).
- In the "Widgets with choices" section, can you add references to the relevant widgets? "A couple of widgets deal with choices" is a bit vague.
comment:6 Changed 6 years ago by
Done :-)
comment:7 Changed 6 years ago by
Nice! I have few more small remarks:
- Can you add a tilda in front of
:attr:'~SelectDateWidget.years'?
- The phrase "The reference below describes which options can be set." feels a bit out of place. It would sit better under the
SimpleFormexample, also including a link to the "Built-in widgets" section.
- Move the
datefield in
SimpleFormto the top (i.e. above
radioand and the
Selectwidget (i.e. when/how are they used together). A code sample might also help, if you can add one.
Sorry to be so picky. Your patch is already really good and it's close to be RFC.
Thanks! :)
comment:8 Changed 6 years ago by
comment:9 Changed 6 years ago by
No problem!
Fixed a reference to
CharField and mentioned format localization as well, while we are at it :-)
comment:10 Changed 6 years ago by
OK, I promise this is the last time I send it back :-)
- Rename
choiceto
choice_fieldin the "Widgets inheriting from the Select widget" section's code sample.
- Clarify what "compress" or a "compressed" value means, in the "MultiWidget" section.
- Also in the "MultiWidget" section, use back-quotes and/or cross-references for types and method names.
comment:11 Changed 6 years ago by
comment:12 Changed 6 years ago by
Used an example from
SpliteDateTimeWidget to explain compress.
comment:13 Changed 6 years ago by
You guys are amazing! Thank you very much!
Just two things:
- Where can I see these changes (or do I need to install stuff and do repository/git things)
- Any chance the import locations (e.g.
from django.forms.widgets import RadioSelectand
from django.forms.extras.widgets import SelectDateWidget) can be included with description/examples. This would be seriously helpful to us new-bees. (Can't use stuff if you don't know how to get it)
comment:14 Changed 6 years ago by 6 years ago by
In concertation with bpeschier on IRC, this is good to go. Thanks for your awesome work!
The widgets doc could certainly do with a simple, concrete example. | https://code.djangoproject.com/ticket/16264 | CC-MAIN-2017-26 | refinedweb | 516 | 74.49 |
Code Safari: Forks, pipes, and the Parallel gem
A few weeks ago, I wrote an article about splitting out work to be done into threads to improve performance of a URL checker. A commenter noted that the parallel gem could be used to achieve the same result, which got me all curious. I investigated the gem and found that not only can it parallelize into threads, it also supports splitting out work into multiple processes.
I wonder how that works?
Breaking it open
As always, I start with a copy of the code, usually found on GitHub:
git clone
The README points us towards
Parallel.map as an entry point to the code. It is easy to find, since everything is in the one file:
lib/parallel.rb. Tracing this through leads us to the
work_in_processes and
worker methods, which is the core of what we are trying to figure out. Let’s start the top of
work_in_processes with the intent of figuring out the structure.
# lib/parallel.rb def self.work_in_processes(items, options, &blk) workers = Array.new(options[:count]).map{ worker(items, options, &blk) } Parallel.kill_on_ctrl_c(workers.map{|worker| worker[:pid] })
This spawns a number of workers, then registers them to be correctly terminated if control C is sent to the parent manager process. Without this, killing your script would cause extra processes to be left running abandoned on your system! The
worker method actually creates the new process, and this is where things start to get interesting.
def self.worker(items, options, &block) # use less memory on REE GC.copy_on_write_friendly = true if GC.respond_to?(:copy_on_write_friendly=) child_read, parent_write = IO.pipe parent_read, child_write = IO.pipe pid = Process.fork do begin parent_write.close parent_read.close process_incoming_jobs(child_read, child_write, items, options, &block) ensure child_read.close child_write.close end end child_read.close child_write.close {:read => parent_read, :write => parent_write, :pid => pid} end
There are three important concepts here that I will cover in turn. The first is the call to
Process.fork. This is a system level call (not available on Windows) that efficiently duplicates the current process to create a new one, called the “child”. For most intents and purposes, the two processes are exactly the same — same local variables, same stack trace, same everything. Ruby then directs the original process to skip over the block given to
Process.fork, but the new one to enter it, allowing different behaviour to be executed in each process. In other words, the block given to
Process.fork is only executed by the new child process.
Having two processes, we now need a way to communicate between them so that we can schedule work to be done. This is where the second important concept comes in:
IO.pipe. Since the two new processes are separate, they can not communicate by changing variables, since though they will initially share the same name and values in each process, they are duplicated so that a change made in the child process will not be seen by the parent. A pipe is a method of communicating between processes (again, not available on Windows). It acts just like a file that can be written to by one process, and read from by another. Parallel sets up two pipes to enable bi-directional communication. We will investigate this method further later in the article, for now just recognize that this is setting up a communication channel.
The last important concept is the
copy_on_write_friendly call, which requires a quick digression into memory management to explain. The reason
fork is so efficient is that though it looks like it is making an exact duplicate, it doesn’t actually copy any memory initially — both processes will read the exact same memory locations. It is only when a process writes to memory that it is copied and duplicated. Not only does this mean a fast start up time for the new processes, but it also allows them to have very small memory footprints if they are only reading and processing, as we could often expect our parallel workers to be doing.
For example, say a typical process was 20mb. Running five instances individually would result in memory usage of 100mb (5 lots of 20), but running one instance and forking it would result in a memory usage of still just 20mb! (It’s actually slightly higher due to some overhead in making a new process, but this is neglible.)
We have a problem though, which is Ruby’s garbage collector (how it manages memory). It uses an algorithm known as “mark-and-sweep”, which is a two step process:
- Scan all objects in memory and write a flag to them indicating whether they are in use or not.
- Clean up all objects not marked as in use.
Did you see the problem in step 1? As soon as the Ruby garbage collector runs it executes a write to every object, triggering a copy of that memory to be made! Even with forking, five instances of our 20mb script will still end up using 100mb of memory.
As indicated by the comment in the code snippet about, some very smart people have solved this problem and released it as Ruby Enterprise Edition. Their FAQ has plenty more detail for you to continue reading if you’re interested.
Communication
There is not much more to say about forking that is relevant, so I want to spend the rest of the article focussing on the communication channel:
IO.pipe. On the child side of the
parallel forks, the results of processing are sent back to the parent by writing suitably encoded Ruby objects — either the result or an exception — to the pipe (see the end of
process_incoming_jobs).
The parent spawns a thread per sub-process that blocks waiting for data to appear on the pipe, then collates the result before sending more work to the process. This continues until there is no more work to schedule.
# lib/parallel.rb:124 workers.each do |worker| listener_threads << Thread.new do begin while output = worker[:read].gets # store output from worker result_index, output = decode(output.chomp) if ExceptionWrapper === output exception = output.exception break elsif exception # some other thread failed break end result[result_index] = output # give worker next item next_index = Thread.exclusive{ current_index += 1 } break if next_index >= items.size write_to_pipe(worker[:write], next_index) end ensure worker[:read].close worker[:write].close end end end
Note that rather than using a
Queue as we did in the last article,
parallel uses
Thread.exclusive to keep a thread-safe counter of the current index.
Wrapping it up
We now have a general idea of how to create and communicate between new processes, let’s try and test our knowledge by building a toy app to verify the methods we have learned about:
fork and
pipe.
reader, writer = IO.pipe process_id = Process.fork do writer.write "Hello" end if process_id # fork will return nil inside the child process # only the parent process wil execute this block puts "Message from child: #{reader.read}" end
At first glance this looks fine, but running it you will find the process hangs. We have missed something important!
read appears to be blocking because it isn’t receiving an end of file signal from the pipe. We can confirm that the communication is working otherwise by sending a newline and using
gets instead (which recieves input up to a newline character):
reader, writer = IO.pipe process_id = Process.fork do writer.write "Hello" end
if process_id puts "Message from child: #{reader.gets}" end
This script works as expected. So why isn’t our first script working? The answer is non-obvious if you are not used to working with concurrent code, but is neatly explained in the
IO.pipe documentation:
The read end of a pipe will not generate an end of file condition if there are any writers with the pipe still open. In the case of the parent process, the
readwill never return if it does not first issue a
writer.close.
Bingo! Though our child process is closing it’s copy of the
writer implicitly when it exits, our parent process still has the original reference to
writer open! We can fix this by closing it before we try to read:
reader, writer = IO.pipe process_id = Process.fork do writer.write "Hello" end if process_id writer.close puts "Message from child: #{reader.read}" end
Here are some further exercises for you to work on:
- Extend our sample script to allow the parent to also send messages to the child.
- What advantages/disadvantages are there to using
Thread.exclusive(as parallel does) rather than
Queue(as our last article did) for scheduling?
Let us know how you go in the comments. Tune in next week for more exciting adventures in the code jungle.
- charles martin | http://www.sitepoint.com/code-safari-forks-pipes-and-the-parallel-gem/ | CC-MAIN-2014-23 | refinedweb | 1,465 | 65.12 |
#include <openvrml/frustum.h>
A frustum is more or less a truncated pyramid. This class represents frustums with their wide end facing down the -z axis, and their (theoretical) tip at the origin. A frustum is a convenient representation of the volume of virtual space visible through the on-screen window when using a perspective projection.
openvrml::child_node::render_child
openvrml::geometry_node::render_geometry
Construct and initialize a frustum.
The field of view should be less than 180 degrees. Extreme aspect ratios are unlikely to work well. The near and far plane distances are always positive (think distance, not position). anear must be less than afar. This is supposed to look like gluPerspective.
Update the plane equations.
The plane equations are derived from the other members.
Vertical field of view.
Horizontal field of view.
Distance to the near clipping plane.
Distance to the far clipping plane.
Left (looking down -z) side clip plane.
Format is (a,b,c,d) where (a,b,c) is the plane normal and d is the plane offset. For the momement the eyepoint is always the origin, so d is going to be 0.
Right clipping plane.
Top clipping plane.
Bottom clipping plane. | http://openvrml.org/doc/classopenvrml_1_1frustum.html | CC-MAIN-2017-30 | refinedweb | 196 | 62.54 |
Antonio Gallardo <agallardo@agssa.net> writes:
>
> Andreas Hartmann dijo:
> > Hi Cocoon developers,
> >
> > if an input module namespace is declared twice, e.g.
> >
> > xmlns: > xmlns: >
> > and <input:param> is used for a required parameter:
> >
> > <input:get-attribute>
> > <input:paramfoo</input:param>
> > <input:paramlist</input:param>
> > </input:get-attribute>
> >
> > a ProcessingException is thrown, because the template
> > "get-namespace-prefix" in logicsheet-util.xsl is matching the first
> > namespace declaration and does not find any parameter tags for this
> > namespace prefix.
> >
> > I think it is not a good practise to rely on namespace prefixes.
> > Wouldn't it be possible to use just the namespace URIs to
> resolve the
> > parameter?
>
> The sample is weird and perhaps a bad practice, but if it is
> allowed, it must be allowed. I made a test. Xerces allow the
> code you wrote above. I made a similar change on another page
> (non XSP) and xerces allow that.
IIRC the namespace spec. pretty explicitly says you shouldn't ever rely
on namespace prefixes, you always have to use the URI for comparison
purposes. For example, nothing stops you from aggregating two sources
of XML where the prefix for the same namespace is different. As such,
the example may be weird, but I don't think it's bad practice... | http://mail-archives.apache.org/mod_mbox/cocoon-dev/200406.mbox/%3C1E0CC447E59C974CA5C7160D2A2854EC097E32@SJMEMXMB04.stjude.sjcrh.local%3E | CC-MAIN-2016-30 | refinedweb | 210 | 57.87 |
NAME
glob.h - pathname pattern-matching types
SYNOPSIS
#include <glob.h>
DESCRIPTION
The <glob.h> header shall define the structures and symbolic constants used by the glob() function. The structure type glob_t shall contain at least the following members: size_t gl_pathc Count of paths matched by pattern. char **gl_pathv Pointer to a list of matched pathnames. size_t gl_offs Slots to reserve at the beginning of gl_pathv. The following constants shall be provided as values for the flags argument: GLOB_APPEND Append generated pathnames to those previously obtained. GLOB_DOOFFS Specify how many null pointers to add to the beginning of gl_pathv. shall be defined as error return values: GLOB_ABORTED The scan was stopped because GLOB_ERR was set or (*errfunc)() returned non-zero. GLOB_NOMATCH The pattern does not match any existing pathname, and GLOB_NOCHECK was not set in flags. GLOB_NOSPACE An attempt to allocate memory failed. GLOB_NOSYS Reserved. The following shall be declared as functions and may also be defined as macros. Function prototypes shall be provided. int glob(const char *restrict, int, int (*)(const char *, int), glob_t *restrict); void globfree (glob_t *); The implementation may define additional macros or constants using names beginning with GLOB_. The following sections are informative.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
The System Interfaces volume of IEEE Std 1003.1-2001, glob(), . | http://manpages.ubuntu.com/manpages/precise/man7/glob.h.7posix.html | CC-MAIN-2016-22 | refinedweb | 218 | 59.6 |
Registers are the fastest locations in the memory hierarchy. But unfortunately, this resource is limited. It comes under the most constrained resources of the target processor. Register allocation is an NP-complete problem. However, this problem can be reduced to graph coloring to achieve allocation and assignment. Therefore a good register allocator computes an effective approximate solution to a hard problem.
The register allocator determines which values will reside in the register and which register will hold each of those values. It takes as its input a program with an arbitrary number of registers and produces a program with finite register set that can fit into the target machine. (See image)
Allocation vs Assignment:
Allocation –
Maps an unlimited namespace onto that register set of the target machine.
- Reg. to Reg. Model: Maps virtual registers to physical registers but spills excess amount to memory.
- Mem. to Mem. Model: Maps some subset of the memory location to a set of names that models physical register set.
Allocation ensures that code will fit the target machine’s reg. set at each instruction.
Assignment –
Maps an allocated name set to physical register set of the target machine.
- Assumes allocation has been done so that code will fit into the set of physical registers.
- No more than ‘k’ values are designated into the registers, where ‘k’ is the no. of physical registers.
General register allocation is a NP complete problem:
- Solved in polynomial time, when (no. of required registers) <= (no. of available physical registers).
- An assignment can be produced in linear time using Interval-Graph Coloring.
Local Register Allocation And Assignment:
Allocation just inside a basic block is called Local Reg. Allocation. Two approaches for local reg. allocation: Top down approach and bottom up approach.
Top Down Approach is a simple approach based on ‘Frequency Count’. Identify the values which should be kept in registers and which should be kept in memory.
Algorithm:
- Compute a priority for each virtual register.
- Sort the registers in into priority order.
- Assign registers in priority order.
- Rewrite the code.
Moving beyond single Blocks:
- More complicated because the control flow enters the picture.
- Liveness and Live Ranges: Live ranges consists of a set of definitions and uses that are related to each other as they i.e. no single register can be common in such couple of instruction/data.
Following is a way to find out Live ranges in a block. A live range is represented as an interval [i,j], where i is the definition and j is the last use.
Global Register Allocation and Assignment:
1. The main issue of a register allocator is minimizing the impact of spill code;
- Execution time for spill code.
- Code space for spill operation.
- Data space for spilled values.
2. Global allocation can’t guarantee an optimal solution for the execution time of spill code.
3. Prime differences between Local and Global Allocation:
- Structure of a global live range is naturally more complex than the local one.
- Within a global live range, distinct references may execute a different number of times. (When basic blocks form a loop)
4. To make the decision about allocation and assignments, global allocator mostly uses graph coloring by building an interference graph.
5. Register allocator then attempts to construct a k-coloring for that graph where ‘k’ is the no. of physical registers.
- In case, the compiler can’t directly construct a k-coloring for that graph, it modifies the underlying code by spilling some values to memory and tries again.
- Spilling actually simplifies that graph which ensures that the algorithm will halt.
6. Global Allocator uses several approaches, however, we’ll see top down and bottom up allocations strategies. Subproblems associated with the above approaches.
- Discovering Global live ranges.
- Estimating Spilling Costs.
- Building an Interference graph.
Discovering Global Live Ranges:
How to discover Live range for a variable?
The above diagram explains everything properly. Lets take the example of Rarp, its been initialised at program point 1 and its last usage is at program point 11. Therefore, Live Rnage of Rarp i.e. Larp is [1,11]. Similarly, others follow up.
Estimating Global Spill Cost:
- Essential for taking a spill decision which includes – address computation, memory operation cost and estimated execution frquency.
- For performance benefits these spilled values are kept typically for Activation record.
- Some embedded processors offers ScratchPad Memory to hold such spilled values.
- Negative Spill Cost: Consecutive load store for a single address needs to be removed as it increases burden, hence incur negative spill cost.
- Infinite Spill Cost: A live range should have infinite spill cost if no other live range ends between its definition and it’s used.
Interference and Interference Graph:
From the above diagram, it can be observed that the live range LRa starts in the first basic block and ends in the last basic block. Therefore it will share an edge with every other live Range i.e. Lrb,Lrc,Lrd. However, Lrb,Lrc,Lrd doesn’t overlap with any other live range excpet Lra so they are only sharing an edge with Lra.
Building an Allocator:
- Note that a k-colorable graph finding is an NP-complete problem, so we need an approximation for this.
- Try with live range splitting into some non-trivial chunks (most used ones).
Top Down Colouring:
- Tries to color live range in an order determined by some ranking functions i.e. priority based.
- If no color is available for a live range, allocator invokes either spilling or splitting to handle uncolored ones.
- Live ranges having k or more neighbors are called constrained nodes and are difficult to handle.
- The unconstrained nodes are comparatively easy to handle.
- Handling Spills: When no color found for some live ranges, spilling is needed to be done, but this may not be a final/ultimate solution of course.
- Live Range Splitting: For uncolored ones, split the live range into sub-ranges, those may have fewer interference than the original one so that some of them can be colored at least.
Chaitin’s Idea:
- Choose an arbitrary node of ( degree < k ) and put it in the stack.
- Remove that node and all its edges from the graph. (This may decrease the degree of some other nodes and cause some more nodes to have degree = k, some node has to be spilled.
- If no vertex needs to be spilled, successively pop vertices off the stack and color them in a color not used by neighbors. (reuse colors as far as possible).
Coalescing copies to reduce degree:
The compiler can use the interference graph to coalesce two live ranges. So by coalescing, what type of benefits can you get?
Comparing Top-Down and Bottom-Up allocator:
- Top-down allocator could adopt the ‘spill and iterate’ philosophy used in bottom-up ones.
- ‘Spill and iterate’ trades additional compile time for an allocation that potentially, uses less spill code.
- Top-Down uses priority ranking to order all the constrained nodes. (However, it colors the unconstrained nodes in an arbitrary order)
- Bottom-up constructs an order in which most nodes are colored in a graph where they are unconstrained.
1 Comments | https://tutorialspoint.dev/computer-science/computer-organization-and-architecture/computer-organization-register-allocation | CC-MAIN-2021-17 | refinedweb | 1,187 | 57.87 |
Products.CacheSetup 1.2.1
Control caching of Plone sites
Introduction
CacheFu speeds up Plone sites transparently using a combination of memory, proxy, and browser caching. Can be used by itself or with Squid, Varnish, and/or Apache. Once installed, your site should run much faster (about 10x faster by itself or about 50x faster with Squid).
CacheFu is a collection of products and recipes. The central product is Products.CacheSetup which when installed via easy_install or buildout takes care of pulling in the rest of the products from the bundle.
The full bundle includes:
-
-
-
-
Additional optional components include some Squid, Varnish, and Apache configuration helpers. See the installation instructions for more info about these.
The latest information about releases can be found at
CacheFu has been tested with Plone 2.5+ and Plone 3.0. For earlier Plone versions, try the CacheFu 1.0.3 bundle instead.
Products.CacheSetup Installation
Products.CacheSetup is the python egg version of the old CacheSetup product. The egg version automatically takes care of installing all the dependancies that make up the CacheFu bundle. However, the proxy cache configs must still be downloaded and configured separately.
References to the "Manual" below refer to the new CacheFu manual nearing completion as of this release. Visit the official CacheFu site,, for the latest instructions.
There are three options for installation, and then some post-installation steps:
(1) Global Install
To install Products.CacheSetup into the global Python environment (or a workingenv) using a traditional Zope 2 instance:
Run easy_install Products.CacheSetup. Find out how to install setuptools (and EasyInstall) here:
If you are using Zope 2.9 (not 2.10), get pythonproducts and install it into your Zope instance via:
python setup.py install --home /path/to/instance
(2) Local Install (standard buildout install)
To install Products.CacheSetup into the local zope instance if you are using zc.buildout and the plone.recipe.zope2instance recipe to manage your project:
Add Products.CacheSetup to the list of eggs to install:
[buildout] ... eggs = ... Products.CacheSetup
Re-run buildout:
$ ./bin/buildout
(3) Local Install (old style Product install)
Because its top level python namespace package is called Products, this package can also be installed in Zope 2 as an old style Zope 2 Product.
For an old style Product install, move (or symlink) the CacheSetup folder of this project (Products.CacheSetup/Products/CacheSetup) into the Products directory of the Zope instance, and restart the server.
Note that in this case, dependancies are not automatically installed so you will have to repeat this process for the rest of the CacheFu bundle: Products.CMFSquidTool, Products.PageCacheManager, and Products.PolicyHTTPCacheManager.
Post-Installation Steps
If installing for the first time:
- After starting up Zope, install the CacheSetup product via the Plone "Add/Remove Products" page
- Optional: Configure via the "Cache Configuration Tool" (see "Configuring CacheFu" in the Manual)
- Optional: Install and configure Squid or Varnish (see below)
If upgrading from a pre-1.2 version:
- Remove the previous version from the Products directory of the instance. CacheSetup, CMFSquidTool, PageCacheManager, and PolicyHTTPCacheManager have all been replaced by Products.CacheSetup, Products.CMFSquidTool, etc. If CacheFu was previously installed in a buildout via plone.recipe.distros, then remove the old CacheFu settings from this section and re-run buildout.
- Manual)
- Optional: Install and configure Squid or Varnish (see below)
- IMPORTANT: There is no upgrade path from the pre-1.0 versions of CacheFu. In this case, the old CacheFu products should be completely uninstalled via the Plone "Add/Remove Products" page and then deleted from the Products directory of the instance BEFORE installing the new version.
Proxy Cache Installation and Configuration
Buildout recipes for building and configuring Squid, Varnish, and Apache are available:
-
-
-
Previously, the CacheFu bundle also included a collection of auto-generated proxy configs for Squid, Varnish, and Apache. Starting with version 1.2, this collection is now maintained as a separate download found at
Changelog
Changelog for the current CacheFu release. For a history of changes prior to this release, see docs/HISTORY.txt
1.2.1 - released 2009-05-17
- Release manager:
- Ricardo Newbery, ric@digitalmarbles.com
- Compatible with:
- Plone 3.2, 3.1, 3.0, and 2.5
Convert view name to string type before looking up matching cache rules. Also fix up base_cache_rule._associateTemplate to ignore NotFound errors. Thanks to Silvio Tomatis for the report. [newbery]
Fixed a Plone 2.5 incompatibility in exportimport/atcontent.py. Thanks to Kai Lautaportti for the patch. [newbery]
Added a workaround to fix creating GenericSetup snapshots. [rossp]
Added at_download purge URLs for files and images. Fixes a problem with stale file downloads. [rossp]
Changed over to a "version-less" naming of policies to make GenericSetup updates more sane. [newbery]
Don't throw an error in Plone 2.5 if all the 'folder_buttons' actions have been deleted/hidden. That's an odd configuration since it makes folder_contents views useless but we should still not throw an error. Fixes [newbery]
Fixed a bug where Accept-Encoding was showing up twice in the Vary header. Also made setVaryHeader a bit smarter about what values are required so instead of throwing a validation error we now just quietly fix the obvious omissions. [newbery]
Added a free-form, syntax-checked field to the list of headers that a headerset can apply. We now support surrogate cache control. [newbery]
A CMFQuickInstaller uninstall/install after a GenericSetup install appears broken somehow. It's as if GS-installed tools do not get properly unregistered by QI (this is unconfirmed), but oddly a zope restart after a QI uninstall fixes this. But if a restart is not done, one consequence is that setTitle never gets called because getToolByName says the cachetool exists already. Since title is a required field but hidden in the edit form, this makes it impossible to enable CacheFu. QI is going away soon anyway so we punt on this bug and just call setTitle unconditionally. [newbery]
Added missing workflow binding for CachePolicy entry in the GenericSetup workflow.xml settings. [newbery]
Added missing title for RuleFolder/HeaderSetFolder entries in the GenericSetup cache settings. [newbery]
Fixed a GS setuphandlers issue where importing ObjectInitializedEvent breaks in Plone 2.5. Thanks to Kai Lautaportti for the report. [newbery]
Fixed a boolean issue seen in Plone 2.5 where setEnabled() fails due to an inappropriate type comparison. Thanks to Kai Lautaportti for the report. Fixes [newbery]
Fixed up the version checking. We now no longer rely on quickinstaller to keep track of the installed version since qi is unreliable on product path changes and during some GS installs. We also now no longer do a "full" disable during version mismatches -- we don't need need to anymore since everything now respects the 'enabled' flag. [newbery]
Fixed up the CacheFu Caching Policy Manager so that it respects the CacheSetup 'enabled' field. We don't have to delete this tool now in order to turn off caching behavior. [newbery]
Use the FasterStringIO from CMFPlone/patches/unicodehacks instead of the standard StringIO to avoid issues due to a mix of strings and unicode. [fschulze]
Improve the GenericSetup export code:
- Also export the title field for header and rule sets.
- PolicyHTTPCacheManagerCacheRule also needs the basic header set fields.
- Import sub-items before importing the object itself so references work correctly.
[wichert]
Add missing title for entries in the GenericSetup cache settings. [wichert]
If we silently ignore the 'enable CacheFu' option when the user is changing the cache tool settings show a very clear warning. [wichert]
Fixed two return values in patch_cmf.py. In Plone 3 you need to return Unicode all the time. Otherwise PageTemplate files in the ZODB would generate an assertion error in pt_render, complaining about the empty string not being Unicode. [hannosch]
Add a vocabulary which lists all header sets. [wichert]
- Author: Geoff Davis <plone-developers at lists sourceforge net>
- Keywords: cache caching
- License: ZPL
- Categories
- Package Index Owner: newbery
- DOAP record: Products.CacheSetup-1.2.1.xml | http://pypi.python.org/pypi/Products.CacheSetup | crawl-002 | refinedweb | 1,323 | 58.28 |
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