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Python | Say I want to debug a simple class with an attribute myattribute . I create a repr method like this : It feels a bit redundant , so I would prefer to use format directly : ... but that fails with an IndexError : tuple index out of range . I understand it that format can not access the self argument , but I do not see w... | class SimpleClass : def __repr__ ( self ) : return `` { 0.myattribute } '' .format ( self ) class SimpleClass : __repr__ = `` { 0.myattribute } '' .format | How can I use ` str.format ` directly as ` __repr__ ` ? |
Python | I have following DataFrame : I want to transform following Dataframe : into dataframe of rows : The products are known ahead.Any idea how to do so ? | data = { 'year ' : [ 2010 , 2010 , 2011 , 2012 , 2011 , 2012 , 2010 , 2011 , 2012 , 2013 ] , 'store_number ' : [ '1944 ' , '1945 ' , '1946 ' , '1947 ' , '1948 ' , '1949 ' , '1947 ' , '1948 ' , '1949 ' , '1947 ' ] , 'retailer_name ' : [ 'Walmart ' , 'Walmart ' , 'CRV ' , 'CRV ' , 'CRV ' , 'Walmart ' , 'Walmart ' , 'CRV ... | Transforming Dataframe columns into Dataframe of rows |
Python | If I try to print the class variable which is a list , I get a Python object . ( These are examples I found on stackoverflow ) .But in this more simple example , it actually prints : I figured this line is the culprit : Contact.all_contacts.append ( self ) in the first sample code . But I 'm not exactly sure whats goin... | class Contacts : all_contacts = [ ] def __init__ ( self , name , email ) : self.name = name self.email = email Contacts.all_contacts.append ( self ) def __str__ ( self ) : return ' % s , < % s > ' % ( self.name , self.email ) c1 = Contacts ( `` Grace '' , `` something @ hotmail.com '' ) print ( c1.all_contacts ) [ < __... | How do I print this class variable ? |
Python | Suppose you find yourself in the unfortunate position of having a dependency on a poorly behaved library . Your code needs to call FlakyClient.call ( ) , but sometimes that function ends up hanging for an unacceptable amount of time.As shown below , one way around this is to wrap the call in its own Process , and use t... | from multiprocessing import Processfrom flaky.library import FlakyClientTIMEOUT_IN_SECS = 10def make_flaky_call ( ) : result = FlakyClient.call ( ) proc = Process ( target=make_flaky_call ) proc.start ( ) proc.join ( TIMEOUT_IN_SECS ) if proc.is_alive ( ) : proc.terminate ( ) raise Exception ( `` Timeout during call to... | How can you safeguard yourself from a flaky library call that might hang indefinitely ? |
Python | Is there a better way to do this ? I feel like I am doing something wrong by being too repetitive . | O = viz.pick ( 1 , viz.WORLD ) BackSetts = [ `` set_b1b '' , `` set_b2a '' , `` set_b1a '' , `` set_b2b '' ] LeftSetts = [ `` set_l1a '' , `` set_l1b '' , `` set_l2a '' , `` set_l1b '' ] NormSetts = [ `` set_nr_a '' , `` set_nr_b '' ] Maps = [ `` MapA '' , '' MapB '' ] if O.name in BackSetts : for i in set ( BackSetts ... | Is there a better way to write this ? |
Python | I want to split array into array with mask and indexlike below into can I do this without loop ? Edit : More examples ... Say , we have an array a with shape [ 10 , 10 , 10 ] where a [ x , y , : ] = [ 0 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ] Now given the mask b = [ 0 , 3 , 7 ] I want the output to be an array c with sh... | a = array ( [ 0 , 1 , 2 , 3 , 4 , 5 ] ) ) b = [ 0,2,3 ] c = array ( [ [ 0 , 2 , 3 ] , [ 1 , 3 , 4 ] , [ 2 , 4 , 5 ] ] ) | can I split numpy array with mask ? |
Python | Thanks in advance for helping.I have a csv file with the following structure : I need a nested JSON for use in D3 or amcharts . With the python script on this page ( https : //github.com/hettmett/csv_to_json ) I could create a nested JSON . The results looks like this : However it is not exactly what I need . The probl... | group1 , group2 , group3 , name , infoGeneral , Nation , ,Phil , info1General , Nation , ,Karen , info2General , Municipality , ,Bill , info3General , Municipality , ,Paul , info4Specific , Province , ,Patrick , info5Specific , Province , ,Maikel , info6Specific , Province , Governance , Mike , info7Specific , Province... | Problem creating nested JSON with python from csv with columns without value |
Python | I 'm learning a bit of python coding and I 'm following this youtube video too to make some practice.Now here is what I 'm running.The strange thing is that for a few buses , the program somehow mixes longitude , latitude and direction for no apparent reason.For example , this is what I 've got right now : I know the c... | import urllibimport operatorfrom xml.etree.ElementTree import parseimport webbrowserfrom showmap import showmapdef getbuses ( ) : u = urllib.urlopen ( 'http : //ctabustracker.com/bustime/map/getBusesForRoute.jsp ? route=22 ' ) data = u.read ( ) f = open ( 'rt22.xml ' , 'wb ' ) f.write ( data ) f.close ( ) doc = parse (... | Ca n't spot a bug in my python code |
Python | I came across a strange result while playing around with Pandas and I am not sure why this would work like this . Wondering if it is a bug.This gives `` 15.0 '' as result.This gives as result a Series : type ( df1.loc [ ' b ' , 'mvl ' ] ) - > pandas.core.series.Seriestype ( df.loc [ ' b ' , 'mvl ' ] ) - > numpy.float64... | cf = pd.DataFrame ( { 'sc ' : [ ' b ' , ' b ' , ' c ' , 'd ' ] , 'nn ' : [ 1 , 2 , 3 , 4 ] , 'mvl ' : [ 10 , 20 , 30 , 40 ] } ) df = cf.groupby ( 'sc ' ) .mean ( ) df.loc [ ' b ' , 'mvl ' ] cf1 = cfcf1 [ 'sc ' ] = cf1 [ 'sc ' ] .astype ( 'category ' , categories= [ ' b ' , ' c ' , 'd ' ] , ordered = True ) df1 = cf1.gr... | Pandas - Category variable and group by - is this a bug ? |
Python | If I write : I get : Why is it coercing them into ints ? It does the same thing in reverse.Output is : Can this be disabled ? Is it a bug ? | d = { 0 : ' a ' , 1 : ' b ' } d [ False ] = ' c 'd [ True ] = 'd'print ( d ) { 0 : ' c ' , 1 : 'd ' } d = { False : ' a ' , True : ' b ' } d [ 0 ] = ' c 'd [ 1 ] = 'd'print ( d ) { False : ' c ' , True : 'd ' } | Dictionary coercion intentional or no ? |
Python | I 've read various `` there is no truly private data in Python instances '' posts , but we 're all aware of using closures in Perl and JavaScript to effectively achieve private data . So why not in Python ? For example : Now we do : What can you do to the instance thing to get read access to the original string ( ignor... | import codecsclass Secret : def __private ( ) : secret_data = None def __init__ ( self , string ) : nonlocal secret_data if secret_data is None : secret_data = string def getSecret ( self ) : return codecs.encode ( secret_data , 'rot_13 ' ) return __init__ , getSecret __init__ , getSecret = __private ( ) > > > thing = ... | Python private instance data revisited |
Python | When inputting 1000 for the range of this code , many ellipse shapes are created , some of which are hard to see . This seems to only happen with the Fibonacci sequence and no other chains of long numbers . Why is this ? | in_range = int ( input ( `` range : `` ) ) fibo_list = [ ] a = 0b = 1count = 0if in_range < 0 : print ( `` faulty '' ) elif in_range == 0 : print ( `` faulty '' ) else : while count < in_range : c = a + b a = b b = c count += 1 fibo_list.append ( a ) print ( fibo_list ) | Why do very large Fibonacci numbers create an ellipse-type shape ? |
Python | so far my dataframe looks like this : I would like to replace the area ' Q ' with ' P ' for every row where the Stage is equal to ' X'.So the result should look like : I tried : It does not work . Help is appreciated ! : ) | ID Area Stage1 P X2 Q X3 P X4 Q Y ID Area Stage1 P X2 P X3 P X4 Q Y data.query ( 'Stage in [ `` X '' ] ' ) [ 'Area ' ] =data.query ( 'Stage in [ `` X '' ] ' ) [ 'Area ' ] .replace ( ' Q ' , ' P ' ) | Replace column value based on value in other column |
Python | I have two dataframes with the same columns : Dataframe 1 : Dataframe 2 : I want to generate a correlation and p-value dataframe of all posible combinations , this would be the result : The problem is that the cartesian product generates more than 3 million tuples . Taking minutes to finish . This is my code , I 've wr... | attr_1 attr_77 ... attr_8userID John 1.2501 2.4196 ... 1.7610Charles 0.0000 1.0618 ... 1.4813Genarito 2.7037 4.6707 ... 5.3583Mark 9.2775 6.7638 ... 6.0071 attr_1 attr_77 ... attr_8petID Firulais 1.2501 2.4196 ... 1.7610Connie 0.0000 1.0618 ... 1.4813PopCorn 2.7037 4.6707 ... 5.3583 userId petID Correlation p-value0 Jo... | Optimizing cartesian product between two Pandas Dataframe |
Python | Somewhat of a python/programming newbie here ... I am trying to come up with a regex that can handle extracting sentences from a line in a text file , and then appending them to a list . The code : Printed Output as per last 5 lines of above code : The contents of 'sample.txt ' : I have been playing around with the reg... | import retxt_list = [ ] with open ( 'sample.txt ' , ' r ' ) as txt : patt = r'.* } [ . ! ? ] \s ? \n ? |.* } .+ [ . ! ? ] \s ? \n ? ' read_txt = txt.readlines ( ) for line in read_txt : if line == `` \n '' : txt_list.append ( `` \n '' ) else : found = re.findall ( patt , line ) for f in found : txt_list.append ( f ) fo... | Python : Extracting Sentences From Line - Regex Needed Based on Criteria |
Python | I am trying to match strings in a column of a data frame with the strings in a column of another data frame and map the corresponding values . The number of rows are different for both data framesExpected output | df1 = data.frame ( name = c ( `` ( CKMB ) Creatinine Kinase Muscle & Brain '' , `` 24 Hours Urine for Sodium '' , `` Antistreptolysin O Titer '' , `` Blood group O '' , lonic_code = c ( `` 27816-8-O '' , `` 27816-8-B '' , `` 1869-7 '' , `` 33914-3 '' ) df2 = data.frame ( Testcomponents = c ( `` creatinine '' , `` blood... | Matching strings in a column of a data frame with the strings in a column of another data frame using R or Python |
Python | I am a newbie to JavaScript , but I am familiar with Python . I am trying to figure out the differences between the Dictionary in Python and the Object in JS.As far as I know , the key in a dictionary in Python needs to be defined in advance , but it could be undefined in an object in JS . However , I am confused about... | var n = 'name ' ; var n2 = n ; var person = { n : 'mike ' } ; person.n # 'mike'person [ ' n ' ] # 'mike'person [ n2 ] # undefinedperson.n2 # undefinedperson [ 'name ' ] # undefinedperson . 'name ' # undefined n = 'name'n2 = nperson = { n : 'mike ' } person [ n ] # 'mike'person [ n2 ] # 'mike'person [ 'name ' ] # 'mike ... | I am so confused about Object in JavaScript |
Python | This is homework , so I do n't expect the answer , just a point in the right direction.In python I have a dictionary that is like so : For example 'Racing Bike ' is the product name and the list of pairs is ( part , amount required ) , respectively.I have to write a function that , given the above dictionary and the pr... | { 'bike101 ' : ( 'Road Bike ' , [ ( 'WH139 ' , 2 ) , ( 'TR102 ' , 2 ) , ( 'TU177 ' , 2 ) , ( 'FR101 ' , 1 ) , ( 'FB101 ' , 1 ) , ( 'BB101 ' , 1 ) , ( 'GS101 ' , 1 ) ] ) , 'bike201 ' : ( 'Mountain Bike ' , [ ( 'WH239 ' , 2 ) , ( 'TR202 ' , 2 ) , ( 'TU277 ' , 2 ) , ( 'FR201 ' , 1 ) , ( 'FB201 ' , 1 ) , ( 'BB201 ' , 1 ) ,... | Finding an element of a list when the list is in a dictionary ? |
Python | So I have a line of code : That throws me this error : But magically fixes itself if I take out the `` input '' : Here is the function specification in the PyTorch docs : https : //pytorch.org/docs/stable/_modules/torch/nn/utils/rnn.html # pack_padded_sequenceI 'm using Python3 and PyTorch 0.4 . Am I missing something ... | packed_embeddings = pack_padded_sequence ( input=embeddings , lengths=lengths , batch_first=True ) File `` /Users/kwj/anaconda3/lib/python3.6/site-packages/torch/onnx/__init__.py '' , line 130 , in might_trace first_arg = args [ 0 ] IndexError : tuple index out of range packed_embeddings = pack_padded_sequence ( embedd... | Is `` input '' a keyword that causes errors when used as a parameter name ( in PyTorch ) ? |
Python | This is n't a practical problem - I 'm just curious about some strange behavior I 've observed , and wondering if I understand the `` is '' operator correctly.Here 's some predictable Python interpreter output : Now let 's define a variable called True : The interpreter will still return `` True '' for boolean operatio... | > > > True is TrueTrue > > > ( 1==1 ) is TrueTrue > > > True = 'abc ' > > > True == 'abc'True > > > True is 'abc'True > > > ( 1==1 ) True > > > ( 1==1 ) is 'abc'False > > > ( 1==1 ) is TrueFalse | Strange behavior when defining a value for True in Python |
Python | for some reason , any mouse event that happens with my program does n't make the image in the window disappear nor reappear , although my on_key_press ( ) function works.I 've tried state flags and declaring a new image resource , but it does n't change anything in the window.Is there a way to make this work ? Should I... | import pygletwindow = pyglet.window.Window ( ) image = pyglet.resource.image ( 'test.png ' ) image.anchor_x = image.width // 2image.anchor_y = image.height // 2state = True @ window.eventdef on_draw ( ) : print ( 'on_draw ( ) called ' ) window.clear ( ) if state : image.blit ( window.width // 2 , window.height // 2 ) @... | Python Pyglet mouse events do n't call on_draw ( ) nor make changes in window |
Python | I am writing code to read data from a CSV file to a pandas dataframe and to get the unique values and concatenate them as a string . The problem is that one of the columns contains the values True and False . So while concatenating the values I am getting the errorI want python to treat True as string rather than boole... | sequence item 0 : expected str instance , bool found import pandas as pddf=pd.read_csv ( ' C : /Users/jaiveeru/Downloads/run_test1.csv ' ) cols=df.columns.tolist ( ) for i in cols : lst=df [ i ] .unique ( ) .tolist ( ) str1 = ' , '.join ( lst ) lst2= [ str1 ] -- -- > 5 str1 = ' , '.join ( lst ) TypeError : sequence ite... | String Join treats True as Boolean rather than string |
Python | I think I 'm overlooking something simple , but I ca n't seem to figure out what exactly . Please consider the following code : I expected that both for-loops would produce the same result , so 4 5 . However , the for-loop that prints the generator exp prints 4 5 6 7 8 9 . I think it has something to do with the declar... | a = [ 2 , 3 , 4 , 5 ] lc = [ x for x in a if x > = 4 ] # List comprehensionlg = ( x for x in a if x > = 4 ) # Generator expressiona.extend ( [ 6,7,8,9 ] ) for i in lc : print ( `` { } `` .format ( i ) , end= '' '' ) for i in lg : print ( `` { } `` .format ( i ) , end= '' '' ) | Unexpected results when comparing list comprehension with generator expression |
Python | I was just trying to learn K-ary tree implementation in Python and came across this link : http : //www.quesucede.com/page/show/id/python-3-tree-implementationIn the tree.py file , there is a section of code like this : What is self [ identifier ] ? Is it a list ? This is really confusing.Can someone explain and/or poi... | class Tree : def __init__ ( self ) : self.__nodes = { } @ property def nodes ( self ) : return self.__nodes def add_node ( self , identifier , parent=None ) : node = Node ( identifier ) self [ identifier ] = node if parent is not None : self [ parent ] .add_child ( identifier ) return node # ... ... def __getitem__ ( s... | What does self [ identifier ] = some_value do in this code ? |
Python | I have a question about this on testing the following code:1,2 , The file object closed when the file_close_test exits because no reference to it.After the exception raised , the file object not closed.so i think the related stack data not released.After exception_wrapper exit , the file closed automatically.can you ex... | def file_close_test ( ) : f = open ( '/tmp/test ' , ' w+ ' ) if __name__ == '__main__ ' : file_close_test ( ) # wait to see whether file closed . import time time.sleep ( 30 ) def file_close_on_exc_test ( ) : f = open ( '/tmp/test ' , ' w+ ' ) raise Exception ( ) def exception_wrapper ( ) : try : file_close_on_exc_test... | when to release function stack data in python ? |
Python | This is actually in a job posting on SO and being a newbie I thought it was interesting . So you get output like the following : To me this is already confusing because I thought izip_longest ( * ( [ iter ( iterable ) ] * n ) ) would run the izip_longest function on a list of n identical iterators so I would have expec... | def partition ( n , iterable ) : p = izip_longest ( * ( [ iter ( iterable ) ] * n ) ) r = [ ] for x in p : print ( x ) # I added this s = set ( x ) s.discard ( None ) r.append ( list ( s ) ) return r partition ( 5 , L ) ( 1 , 2 , 3 , 4 , None ) Out [ 86 ] : [ [ 1 , 2 , 3 , 4 ] ] p = izip_longest ( * ( [ iter ( iterable... | What does this function do ? ( Python iterators ) |
Python | I have two images , an analysis image and an ROI Mask image ( the ROI Mask image is below ) .What I want to do is to measure the RGB mean value in an area of the analysis image selected by the ROI Mask image . I am doing this by using a for loop but it takes too long.Is there any way to make this simpler ? | import cv2import numpy as npfrom statistics import meanimg=cv2.imread ( `` Analysis.jpg '' , 1 ) mask=cv2.imread ( `` ROI_Mask.jpg '' , 0 ) height = im.shape [ 0 ] width = im.shape [ 1 ] R_value= [ ] G_value= [ ] B_value= [ ] for x in range ( width ) : for y in range ( height ) : if mask [ y ] [ x ] ! =0 : b , g , r=im... | How do I measure RGB mean in a unique ROI ? |
Python | For some reason , I need to be able to delete all the children ( in some sense ) that were originated by some method of the class . Here is an example : What I want is somehow to append generated class B from gen_b to A ( ) .children so that : Additionally , I need this for cython ( I use cdef classes ) , so maybe ther... | class A ( ) : def __init__ ( self ) : self.a_val = 56 self.children = list ( ) def __del__ ( self ) : del self.children def gen_b ( self ) : return B ( self.a_val ) class B ( ) : def __init__ ( self , val ) : self.a_val = val self.b_val = 87 a_class = A ( ) b_generated = a_class.gen_b ( ) del a_class # b_generated is a... | Delete all variables ( classes ) generated by class method python |
Python | Consider the following operation in the limit of low length iterables , Setting as a list is 25 % faster than using a generator expression ? Why is this the case as setting as a list is an extra operation.Note : In both runs I obtained the warning : The slowest run took 6.42 times longer than the fastest . This could m... | d = ( 3 , slice ( None , None , None ) , slice ( None , None , None ) ) In [ 215 ] : % timeit any ( [ type ( i ) == slice for i in d ] ) 1000000 loops , best of 3 : 695 ns per loopIn [ 214 ] : % timeit any ( type ( i ) == slice for i in d ) 1000000 loops , best of 3 : 929 ns per loop import timeit , pylab , multiproces... | Is it faster to iterate a small list within an any ( ) statement ? |
Python | I am having a dataset with dates and company names . I only want to keep rows such that the combination of the company name and the date appeared in the dataset at least twice . To illustrate the problem , let us assume I have the following dataframe : My desired output would be : I would know how to drop the rows base... | df1 = pd.DataFrame ( np.array ( [ [ '28/02/2017 ' , 'Apple ' ] , [ '28/02/2017 ' , 'Apple ' ] , [ '31/03/2017 ' , 'Apple ' ] , [ '28/02/2017 ' , 'IBM ' ] , [ '28/02/2017 ' , 'WalMart ' ] , [ '28/02/2017 ' , 'WalMart ' ] , [ '03/07/2017 ' , 'WalMart ' ] ] ) , columns= [ 'date ' , 'keyword ' ] ) df2 = pd.DataFrame ( np.a... | Drop rows in pandas if records in two columns do not appear together at least twice in the dataset |
Python | I am working on a project where very specific scheduling is needed ( and why I am not using a library ) . It works , but I am trying to find a faster solution to the following problem : We have employees requesting hours every week . They input their total availability for the week ( ex : 8-1 M , W , R ) . They all mus... | # let availability be the string of availability availability = `` 8,9,10,11 ; 8,9 ; ; 8,9,10,11 ; '' poss_times = availability.split ( `` ; '' ) # where I put into one array with each day letter in front sched= [ ] sched.extend ( [ `` m '' + day for day in list ( filter ( None , poss_times [ 0 ] .split ( `` , '' ) ) )... | How to efficiently and quickly find valid combinations out of an array of string elements for employee scheduling ? |
Python | I wrote a simple prime sieve ( an unbounded sieve of Eratosthenes ) using Python , but for some reason , it is n't working correctly . Here is the sieve : Unfortunately , this is n't working . Instead , it just returns the same values as the count ( 2 ) iterator would.For comparison , this : will print : while the siev... | from itertools import countdef sieve ( ) : nums = count ( 2 ) while True : n = next ( nums ) nums = filter ( lambda k : k % n ! = 0 , nums ) yield n nums = count ( 2 ) print ( next ( nums ) ) nums = filter ( lambda k : k % 2 ! = 0 , nums ) print ( next ( nums ) ) nums = filter ( lambda k : k % 2 ! = 0 , nums ) print ( ... | Creating a simple prime sieve in Python |
Python | Ok , this might be a very stupid question and it might not be possible , or I am thinking in a twisted way . So , consider this : Ok , here we have two classes : MyClass is just something very ordinary and nothing special . It has two instance attributes : x and y.MyList , on the other hand , should be a class which de... | class MyClass : def __init__ ( self , x ) : self.x = x self.y = self.x ** 2class MyList : def __init__ ( self , list ) : self.list = list def __iter__ ( self ) : return iter ( self.list ) foo = [ MyClass ( x=1 ) , MyClass ( x=2 ) ] bar = MyList ( list=foo ) for i in bar : print ( i.x , i.y ) | Define what class contains |
Python | I have two 1-dimensional numpy.ndarray objects , and want to work out which elements in the first array are within dx of any element in the second.What I have currently is which returns a timeit result as followsWhat 's the best way to optimise the find_all_close function , especially if a and b are guaranteed to be fl... | # setupnumpy.random.seed ( 1 ) a = numpy.random.random ( 1000 ) # create one arraynumpy.random.seed ( 2 ) b = numpy.random.random ( 1000 ) # create second arraydx = 1e-4 # close-ness parameter # function I want to optimisedef find_all_close ( a , b ) : # compare one number to all elements of b def _is_coincident ( t ) ... | What 's the most efficient way to find which elements of one array are close to any element in another ? |
Python | I am currently writing a program to model Dijkstra 's algorithm , however I am having some trouble the graph in its current form below : I want to get the graph in the form such as the one belowWould this be possible ? | G = [ [ ' a ' , ' b ' , ' c ' , 'd ' , ' e ' , ' f ' , ' g ' , ' h ' , ' i ' , ' j ' ] , [ ( { ' a ' , ' b ' } , 4 ) , ( { ' a ' , ' c ' } , 6 ) , ( { ' a ' , 'd ' } , 8 ) , ( { ' b ' , ' e ' } , 1 ) , ( { ' b ' , ' f ' } , 9 ) , ( { ' c ' , ' f ' } , 2 ) , ( { 'd ' , ' g ' } , 7 ) , ( { 'd ' , ' h ' } , 1 ) , ( { ' e ... | Converting a graph into dictionary form |
Python | Does Python support conditional structure in regex ? If yes , why I ca n't have the following ( using lookahead in the ifpart ) right ? Any way to make Python support it ? Using backreference as the if part works , however : http : //www.regular-expressions.info/conditional.html says Conditionals are supported by the J... | > > > p = re.compile ( r ' ( ? ( ? =regex ) then|else ) ' ) Traceback ( most recent call last ) : File `` < stdin > '' , line 1 , in < module > File `` /usr/lib/python2.7/re.py '' , line 190 , in compile return _compile ( pattern , flags ) File `` /usr/lib/python2.7/re.py '' , line 242 , in _compile raise error , v # i... | Does Python support conditional structure in regex ? |
Python | I have a YAML file that goes as ( just an example ) : I want to read this file , and do some stuff with bs and cs . The problem is that I ca n't read this file as a dictionary using yaml.load ( ) , since it will only give me { ' a ' : { ' b ' : 3 } } . Instead , I want to read it as a list of dictionaries , i.e , I wan... | a : b : 1 a : b : 2 c : 1a : b : 3 [ { ' a ' : { ' b ' : 1 } } , { ' a ' : { ' b ' : 2 , ' c ' : 1 } } , { ' a ' : { ' b ' : 3 } } ] | Read YAML file as list |
Python | I am using the Flask-Mail library for my Flask application to send a default welcome email to the user when they sign up to be added to the newsletter . After debugging the library I found that it can only handle one connection at a time to send a message and will then automatically close the connection . If the backen... | import osimport redisfrom rq import Worker , Queue , Connectionlisten = [ 'high ' , 'default ' , 'low ' ] redis_url = os.environ.get ( 'REDISTOGO_URL ' ) conn = redis.from_url ( redis_url ) if __name__ == '__main__ ' : with Connection ( conn ) : worker = Worker ( map ( Queue , listen ) ) worker.work ( ) from flask impo... | Flask-Mail queue messages to be sent to different emails |
Python | I am working on a leetcode problem `` wordLadder '' Given two words ( beginWord and endWord ) , and a dictionary 's word list , find the length of shortest transformation sequence from beginWord to endWord , such that : Only one letter can be changed at a time . Each transformed word must exist in the word list . Note ... | Input : beginWord = `` hit '' , endWord = `` cog '' , wordList = [ `` hot '' , '' dot '' , '' dog '' , '' lot '' , '' log '' , '' cog '' ] Output : 5Explanation : As one shortest transformation is `` hit '' - > `` hot '' - > `` dot '' - > `` dog '' - > `` cog '' , return its length 5 . Input : beginWord = `` hit '' end... | Exhaustively get all the possible combinations of a word of three lettters |
Python | I was just looking at the implementation of functools.lru_cache , when I stumbled across this snippet : I am familiar with circular and doubly linked lists . I am also aware that new_list = my_list [ : ] creates a copy of my_list.When looking for slice assignments or other implementations of circular doubly linked list... | root = [ ] # root of the circular doubly linked listroot [ : ] = [ root , root , None , None ] # initialize by pointing to self | What is happening when I assign a list with self references to a list copy with the slice syntax ` mylist [ : ] = [ mylist , mylist , ... ] ` ? |
Python | I have the following dictionary : And for this dictionary I want write a function that returns the three key-value pairs that have the highest values ( So in this case key 18 , 19 , 20 ) .I came up with the following : This gives me a list of the max-values I want to lookup . But how do I proceed from here ? Is there a... | ' { 0 : 0 , 1 : 11 , 2 : 26 , 3 : 43 , 4 : 14 , 5 : 29 , 6 : 34 , 7 : 49 , 8 : 49 , 9 : 108 , 10 : 124 , 11 : 108 , 12 : 361 , 13 : 290 , 14 : 2118 , 15 : 5408 , 16 : 43473 , 17 : 109462 , 18 : 111490 , 19 : 244675 , 20 : 115878 , 21 : 6960 } ' cachedict = nr_of_objects_per_century ( ) # Dictionary mentioned abovedef t... | Returning the three maximal values in a dictionary |
Python | I 've run into this problem a few times in different situations but my setup is the following : I have two Django models files . One that contains User models and CouponCodes that a user can use to sign up for a Course . Those are both in the account/models.py file . Course and the related many-to-many field are in a d... | from account import models as amodclass Course ( ExtendedModel ) : stuff = stuff class CouponCode ( ExtendedModel ) : assigned_course = UniqueIDForeignKey ( `` course.Course '' , blank=True , null=True , related_name='assigned_coupon_code_set ' ) ... ... @ staticmethod def assign_batch ( c , upper_limit ) : import cour... | Python/Django : Why does importing a module right before using it prevent a circular import ? |
Python | When I had a list that was in format of I could use However now lets say I have multiple values such as I have no idea how to go about creating a dict so that it would show the first name as the key and the following values as the value.Thanks in advance | list1 = [ [ James,24 ] , [ Ryan,21 ] , [ Tim,32 ] ... etc ] dic1 =dict ( list1 ) list1 = [ [ James,24 , Canada , Blue , Tall ] , [ Ryan,21 , U.S. , Green , Short [ Tim,32 , Mexico , Yellow , Average ] ... etc ] | Converting List to Dict |
Python | I am wanting to check if a list has a specific sequence of elements . I have sorted the list which contains 7 elements , I now want to check of the first 4 are the same as each other and the last 3 are the same as each other . For what I want to achieve to be True the list would be like this : I hope this makes what I ... | list = [ ' 1 ' , ' 1 ' , ' 1 ' , ' 1 ' , ' 2 ' , ' 2 ' , ' 2 ' ] | Checking a List for a Sequence |
Python | In the following data , I am trying to run a simple markov model.Say I have a data with following structure : Block M represents data from one set of catergories , so does block S.The data are the strings which are made by connecting letter along the position line . So , the string value for M1 is A-T-C-G , and so is f... | pos M1 M2 M3 M4 M5 M6 M7 M8 hybrid_block S1 S2 S3 S4 S5 S6 S7 S81 A T T A A G A C A|C C G C T T A G A2 T G C T G T T G T|A A T A T C A A T3 C A A C A G T C C|G G A C G C G C G4 G T G T A T C T G|T C T T T A T C T | How to read two lines from a file and create dynamics keys in a for-loop ? |
Python | I have the following list of strings : I want to obtain a list that has , say , these same elements repeated n times . If n=3 I 'd get : What I am trying is this : But what I obtain is this : If I try this : I obtain : What am I missing ? | l1 = [ 'one ' , 'two ' , 'three ' ] l2 = [ 'one ' , 'one ' , 'one ' , 'two ' , 'two ' , 'two ' , 'three ' , 'three ' , 'three ' ] l2 = [ 3*i for i in l1 ] l2 = [ 'oneoneone ' , 'twotwotwo ' , 'threethreethree ' ] l2 = [ 3* ( str ( i ) + '' , '' ) for i in l1 ] l2 = [ 'one , one , one ' , 'two , two , two ' , 'three , t... | Python : expand list of strings by adding n elements for each original element |
Python | I am implementing an array-like object that should be interoperable with standard numpy arrays . I just hit an annoying problem that narrows down to the following : This yields the following output : Clearly , rather than calling MyArray ( ) .__rmul__ ( array ( [ 1,2,3 ] ) ) as I had hoped , __rmul__ is called for ever... | class MyArray ( object ) : def __rmul__ ( self , other ) : return MyArray ( ) # value not important for current purposefrom numpy import arrayprint array ( [ 1,2,3 ] ) * MyArray ( ) [ < __main__.MyArray instance at 0x91903ec > < __main__.MyArray instance at 0x919038c > < __main__.MyArray instance at 0x919042c > ] | numpy coercion problem for left-sided binary operator |
Python | I 'm creating an application with python to calculate duct-tape overlapping ( modeling a dispenser applies a product on a rotating drum ) .I have a program that works correctly , but is really slow . I 'm looking for a solution to optimize a for loop used to fill a numpy array . Could someone help me vectorize the code... | import numpy as npimport matplotlib.pyplot as plt # Some parameterswidth = 264bbddiam = 940accuracy = 4 # 2 points per pixeldrum = np.zeros ( accuracy**2 * width * bbddiam ) .reshape ( ( bbddiam * accuracy , width * accuracy ) ) # The `` slow '' functiondef line_mask ( drum , coef , intercept , upper=True , accuracy=ac... | Vectorize a for loop in numpy to calculate duct-tape overlaping |
Python | I understand there are at least 3 kinds of methods in Python having different first arguments : instance method - instance , i.e . selfclass method - class , i.e . clsstatic method - nothingThese classic methods are implemented in the Test class below including an usual method : In Python 3 , the unknown_mthd can be ca... | class Test ( ) : def __init__ ( self ) : pass def instance_mthd ( self ) : print ( `` Instance method . '' ) @ classmethod def class_mthd ( cls ) : print ( `` Class method . '' ) @ staticmethod def static_mthd ( ) : print ( `` Static method . '' ) def unknown_mthd ( ) : # No decoration -- > instance method , but # No s... | Are there more than three types of methods in Python ? |
Python | I am working on an interactive plotting script using matplotlib version 3.2.2 and tkinter.When the script is run , the first window looks like this : Furthermore , the rcParams are updated and plotted once the Plot figure button is clicked : If I now hit the button Change plot settings and change for instance the marke... | `` `` '' This is a script for interactively plotting a scatterplot and changing the plot params . `` `` '' import numpy as npimport matplotlib as mplimport matplotlib.styleimport randommpl.use ( 'TkAgg ' ) import numpy as npfrom matplotlib.backends.backend_tkagg import FigureCanvasTkAggfrom matplotlib.figure import Fig... | Matplotlib rcParams ignored when plotting |
Python | I 'm using the Mirametrix S2 gaze tracking device . In the API docs ( v1.1 ) , it says that the ENABLE_SEND_GPI command allows a tracking client to insert data into the gaze stream . Copying some of the example code , I tried the following : I get the following in response : I 've tried many different combinations of i... | sock.send ( ' < SET ID= '' ENABLE_SEND_GPI '' STATE= '' 1 '' / > \r\n ' ) sock.send ( ' < SET ID= '' GPI_NUMBER '' VALUE= '' 1 '' / > \r\n ' ) sock.send ( ' < SET ID= '' GPI1 '' VALUE= '' INTERVAL '' / > \r\n ' ) < ACK ID= '' ENABLE_SEND_GPI '' STATE= '' 1 '' / > < ACK ID= '' GPI_NUMBER '' VALUE= '' 1 '' / > < ACK ID= ... | Mirametrix S2 gaze tracker : Sending general purpose input ( GPI ) values always fails |
Python | What 's the rationale behind not allowing * in relative imports ? e.g.or doing a relative import directly : | from ..new_tool import * import ..new_tool | python : What 's the rationale behind not allowing * in relative imports ? |
Python | The intended objective of function foo is to add the number provided as argument to the list and , in case it is 0 , reset the list . First I wrote this program : output : but it looks like bar = [ ] is ignored . Then I changed bar = [ ] with bar.clear ( ) and it works as I thought : output : I have n't understood why ... | def foo ( n , bar = [ ] ) : if n == 0 : bar = [ ] print ( `` list empty '' ) else : bar.append ( n ) for y in bar : print ( y , end= ' , ' ) print ( ) foo ( 5 ) foo ( 3 ) foo ( 0 ) foo ( 6 ) 5 , 5 , 3 , list empty5 , 3 , 6 , def foo ( n , bar = [ ] ) : if n == 0 : bar.clear ( ) print ( `` list empty '' ) else : bar.app... | How is list.clear ( ) different from list = [ ] ? |
Python | I am trying to create a custom estimator based on scikit learn . I have written the below dummy code to explain my problem . In the score method , I am trying to access mean_ calulated in fit . But I am unable to . What I am doing wrong ? I have tried many things and have done this referring three four articles . But d... | import numpy as npfrom sklearn.model_selection import cross_val_scoreclass FilterElems : def __init__ ( self , thres ) : self.thres = thres def fit ( self , X , y=None , **kwargs ) : self.mean_ = np.mean ( X ) self.std_ = np.std ( X ) return self def predict ( self , X ) : # return sign ( self.predict ( inputs ) ) X = ... | Custom scikit-learn scorer ca n't access mean after fit |
Python | I want to use Keras Resnet50 model using OpenCV for reading and resizing the input image.I 'm using the same preprocessing code from Keras ( with OpenCV I need to convert to RGB since this is the format expected by preprocess_input ( ) ) .I get slightly different predictions using OpenCV and Keras image loading . I do ... | import numpy as npimport jsonfrom tensorflow.keras.applications.resnet50 import ResNet50from tensorflow.keras.preprocessing import imagefrom tensorflow.keras.applications.resnet50 import preprocess_input , decode_predictionsimport cv2model = ResNet50 ( weights='imagenet ' ) img_path = '/home/me/squirle.jpg ' # Keras pr... | Resnet50 produces different prediction when image loading and resizing is done with OpenCV |
Python | I want to be able to do something like : In other words , is there a hashable equivalent for Counter ? Note that I ca n't use frozenset since I have repeated elements that I want to keep in the key.Edit : In my actual application , the objects in foo may not be comparable with each other so the list can not be sorted . | foo = Counter ( [ 'bar ' , 'shoo ' , 'bar ' ] ) tmp = { } tmp [ foo ] = 5 | Unordered list as dict key |
Python | I have 2 models that look like this : models.pyThen in the admin , I have inlined the related models to make it easy to make changes regardless of the object type you have open.admin.pyHowever , if you add a Client to a Deal and then open the Client detail page , the corresponding deal does not appear . Is there someth... | class Client ( models.Model ) : deal = models.ManyToManyField ( 'Deal ' , related_name= '' clients '' ) class Deal ( models.Model ) : client = models.ManyToManyField ( Client , related_name= '' deals '' ) class ClientInline ( admin.TabularInline ) : model = Deal.client.throughclass DealAdmin ( admin.ModelAdmin ) : inli... | Django related model not updating related object in admin |
Python | I am trying to implement a series of statistical operations , and I need help vectorizing my code.The idea is to extract NxN patches from two images , the compute a distance metric between these two patches.To do this , first I construct the patches with the following loops : This takes about 10 seconds to complete , a... | params = [ ] for i in range ( 0 , patch1.shape [ 0 ] ,1 ) : for j in range ( 0 , patch1.shape [ 1 ] ,1 ) : window1 = np.copy ( imga [ i : i+N , j : j+N ] ) .flatten ( ) window2 = np.copy ( imgb [ i : i+N , j : j+N ] ) .flatten ( ) params.append ( ( window1 , window2 ) ) print ( f '' We took { time ( ) - t0:2.2f } secon... | Advice on vectorizing block-wise operations in Numpy |
Python | This one has me entirely baffled.This code works perfectly with the collections line commented out . However , when I comment out the row = dict line and remove the comment from the collections line things get very strange . There are about 4 million of these rows being generated and appended to asset_hist.So , when I ... | asset_hist = [ ] for key_host , val_hist_list in am_output.asset_history.items ( ) : for index , hist_item in enumerate ( val_hist_list ) : # row = collections.OrderedDict ( [ ( `` computer_name '' , key_host ) , ( `` id '' , index ) , ( `` hist_item '' , hist_item ) ] ) row = { `` computer_name '' : key_host , `` id '... | Python OrderDict sputtering as compared to dict ( ) |
Python | It is well known , that small bytes-objects are automatically `` interned '' by CPython ( similar to the intern-function for strings ) . Correction : As explained by @ abarnert it is more like the integer-pool than the interned strings.Is it possible to restore the interned bytes-objects after they have been corrupted ... | % % cythondef do_bad_things ( ) : cdef bytes b=b ' a ' cdef const unsigned char [ : ] safe=b cdef char *unsafe= < char * > & safe [ 0 ] # who needs const and type-safety anyway ? unsafe [ 0 ] =98 # replace through ` b ` import ctypesimport sysdef do_bad_things ( ) : b = b ' a ' ; ( ctypes.c_ubyte * sys.getsizeof ( b ) ... | Is it possible to restore corrupted “ interned ” bytes-objects |
Python | Here is some code I wrote for parallelizing the creation of a dictionaryparallelize.pyHere is the output for size 1 mil with threshold 1 milHere is output for size = 10mil with threshold 1 milHere is the output for size 100 mil with threshold 10 mil , the worst part here is even before the combining , the map_async sti... | if __name__ == `` __main__ '' : import time from multiprocessing import Pool def assign_dict ( alist ) : return { x : x for x in alist } my_dict = { } size = 10000000 threshold=10000000 my_list=list ( range ( size ) ) start=time.time ( ) my_dict=assign_dict ( my_list ) end=time.time ( ) print ( `` check seq '' , end-st... | Python3 parallel code via multiprocessing.pool is slower than sequential code |
Python | I am building a Python utility that will involve mapping integers to word strings , where many integers might map to the same string . From my understanding , Python interns short strings and most hard-coded strings by default , saving memory overhead as a result by keeping a `` canonical '' version of the string in a ... | import systop = 10000non1 = [ ] non2 = [ ] for i in range ( top ) : s1 = ' { :010d } '.format ( i ) s2 = ' { :010d } '.format ( i ) non1.append ( s1 ) non2.append ( s2 ) same = Truefor i in range ( top ) : same = same and ( non1 [ i ] is non2 [ i ] ) print ( `` non : `` , same ) # prints Falsedel non1 [ : ] del non2 [ ... | In Python , why do separate dictionary string values pass `` in '' equality checks ? ( string Interning Experiment ) |
Python | Suppose you use a transaction to process a Stripe payment and update a user entity : It is possible that the Stripe API call succeeds but that the put fails because of contention . The user would then be charged , but his account would n't reflect the payment.You could pull the Stripe API call out of the transaction an... | @ ndb.transactionaldef process_payment ( user_key , amount ) : user = user_key.get ( ) user.stripe_payment ( amount ) # API call to Stripe user.balance += amount user.put ( ) | GAE/P : Transaction safety with API calls |
Python | Given a list [ 2,8,13,15,24,30 ] , all the elements of which are supposed to be in range ( 31 ) . Now I want to slice it into 3 lists , first list with numbers from 0 to 10 , the second one with numbers from 11 to 20 , and the others into the rest.Here is my ugly code : I do n't think this is a good way to do it . Any ... | numbers = [ 2,8,13,15,24,30 ] mylist = [ [ ] , [ ] , [ ] ] # I hate this the most ... for i in numbers : if i < = 10 : mylist [ 0 ] .append ( i ) elif i > 10 and i < = 20 : mylist [ 1 ] .append ( i ) else : mylist [ 2 ] .append ( i ) print mylist | Elegant way to slice a list with a condition |
Python | Consider the following session . How are the differences explained ? I thought that a += b is a syntactical sugar of ( and thus equivalent to ) a = a + b . Obviously I 'm wrong.Thank you | > > > import numpy as np > > > a = np.arange ( 24 . ) .reshape ( 4,6 ) > > > print a [ [ 0 . 1 . 2 . 3 . 4 . 5 . ] [ 6 . 7 . 8 . 9 . 10 . 11 . ] [ 12 . 13 . 14 . 15 . 16 . 17 . ] [ 18 . 19 . 20 . 21 . 22 . 23 . ] ] > > > for line in a : ... line += 100 ... > > > print a # a has been changed [ [ 100 . 101 . 102 . 103 . ... | Processing data by reference or by value in python |
Python | For example : But os.__dict__ shows there is a __dict__ attribute . | > > > import os > > > '__dict__ ' in dir ( os ) False | Why does dir of a module show no __dict__ ? ( python ) |
Python | given two general numpy 1-d arrays ( no guarantees about values whatsoever ) , I need to check if one is a sub-array of the other.It 's short and easy to do by casting to strings , but probably not the most efficient : is there an efficient builtin/native numpy way to do this ? | import numpy as npdef is_sub_arr ( a1 , a2 ) : return str ( a2 ) .strip ( ' [ ] ' ) in str ( a1 ) .strip ( ' [ ] ' ) arr1 = np.array ( [ 9 , 1 , 3 , 2 , 7 , 2 , 7 , 2 , 8 , 5 ] ) arr2 = np.array ( [ 3 , 2 , 7 , 2 ] ) arr3 = np.array ( [ 1,3,7 ] ) print ( is_sub_arr ( arr1 , arr2 ) ) # Trueprint ( is_sub_arr ( arr1 , ar... | Numpy : check if 1-d array is sub-array of another |
Python | I look up online and know that list.pop ( ) has O ( 1 ) time complexity but list.pop ( i ) has O ( n ) time complexity . While I am writing leetcode , many people use pop ( i ) in a for loop and they say it is O ( n ) time complexity and in fact it is faster than my code , which only uses one loop but many lines in tha... | class Solution ( object ) : def removeDuplicates ( self , nums ) : `` '' '' : type nums : List [ int ] : rtype : int `` '' '' left , right = 0 , 0 count = 1 while right < len ( nums ) -1 : if nums [ right ] == nums [ right+1 ] : right += 1 else : nums [ left+1 ] =nums [ right+1 ] left += 1 right += 1 count += 1 return ... | Python list.pop ( i ) time complexity ? |
Python | I want to use a function f ( x ) in python . Something like ax^2 + bx + c ( polynomials ) . I want to do that using a for loop and a list . This is what I have so far : for example : when I fill in f ( [ 5,2,3 ] ,5 ) I have to get:3*5^0 + 2*5^1 + 5*5^2 . Does somebody know how I can change my code so the output will be... | def f ( a , x ) : for i in range ( 0 , len ( a ) ) : i = ( [ a ] *x**i ) print ( i ) | Using a normal function f ( x ) in python |
Python | I am using django-haystack and I am trying to implement a way to append the page number to a pdf link in order to open it in the specific page . My goal is to open the pdf in the page where the first hit is found . I know the position of the hit in my document and the position where the page changes . For example i kno... | from django.shortcuts import renderfrom haystack.utils.highlighting import Highlighterdef getPage ( request ) : pos = Highlighter.getPos ( ) print ( pos ) return render ( request , 'search/_result_object.html ' , { 'pos ' : pos } ) < ul > { % for element in pos % } < li > { { element } } < /li > { % endfor % } < /ul > | Django pass Haystack highlighter result to a view |
Python | I understand that the python builtin id ( ) returns an ID that is unique for the lifetime of an object . Objects with non-overlapping lifetimes , I understand , can end up with the same ID . However , I am trying to understand this rather confusing behavior : And in fact across multiple interpreter instances , the beha... | > > > id ( matplotlib.image.BboxImage.set_cmap ) 4424372944 > > > id ( numpy.ma.core.MaskedArray.sum ) 4424372944 Mac : ~ $ python2.7 -c `` import matplotlib.image ; import numpy ; print id ( matplotlib.image.BboxImage.set_cmap ) , id ( numpy.ma.core.MaskedArray.sum ) '' 4343186208 4343186208Mac : ~ $ python2.7 -c `` i... | Repeatable id clashes on python objects |
Python | I 'm trying to convert numbers to excel column letters.Code : Desired output : Actual output : | def num2col ( num ) : letters = `` while num : mod = num % 26 num = num // 26 letters += chr ( mod + 64 ) return `` .join ( reversed ( letters ) ) print num2col ( 25 ) , num2col ( 26 ) , num2col ( 27 ) print num2col ( 51 ) , num2col ( 52 ) , num2col ( 53 ) print num2col ( 77 ) , num2col ( 78 ) , num2col ( 79 ) Y Z AAAY... | Python character function , where is the `` Z '' ? |
Python | I 've got some code ( that someone else wrote ) : which I think could be re-written as : This would of course fail if someone passed in attrs=None , but is that something to be expected ? Is there a penalty for the attrs= { } ( extra wasted dict creation ? ) I 'm still too new to python to answer these questions , but ... | def render ( self , name , value , attrs=None ) : if not attrs : attrs = { } attrs.update ( { 'class ' : 'ui-autocomplete-input ' } ) def render ( self , name , value , attrs= { } ) : attrs.update ( { 'class ' : 'ui-autocomplete-input ' } ) > > > def x ( attrs= { } ) : ... attrs.update ( { ' a ' : ' b ' } ) ... print a... | Best way to deal with default params in Python ? |
Python | I try to concatenate the following strings to a pathleads to To get to the desired outcome I need to remove the first forward slash in the variable lpIs there a more elegant to do it as I do not want to parse all identifiers for a forwarding slash in the beginning ? | mr = `` /mapr '' cn = `` 12.12.12 '' lp = `` /data/dir/ '' vin = `` var '' os.path.join ( mr , cn , lp , vin ) '/data/dir/var ' lp = `` data/dir/ '' os.path.join ( mr , cn , lp , vin ) '/mapr/12.12.12/data/dir/var ' | connecting multiple strings to path in python with slashes |
Python | I have a dictionary that needs to be sorted . I understand that a dictionary can not be sorted , so I am building a list to perform a sort based upon the index . The problem I am having is that there are duplicate values across multiple keys ; also , the values can be multiple lists.Dictionary : I need to be able to so... | my_dict = { ' 1 ' : [ 'Red ' , 'McDonald\'s ' ] , ' 2 ' : [ [ 'Orange ' , 'Wendy\'s ' ] , [ 'Purple ' , 'Cookout ' ] ] , ' 3 ' : [ 'Yellow ' , 'Longhorn ' ] , ' 4 ' : [ 'Green ' , 'Subway ' ] , ' 5 ' : [ 'Blue ' , 'Chipotle ' ] , ' 6 ' : [ 'Indigo ' , 'Taco Bell ' ] , ' 7 ' : [ [ 'Violet ' , 'Steak n Shake ' ] , [ 'Dar... | Sorting a dictionary with multiple sized values |
Python | I have a greyscale image in numpy array format ( standard OpenCV format ) . Normal image , uint8 , all values between 0 and 255 . When I run : I get : But when I run : I get : And what 's really weird is that if I resize the pyplot image window , those line artifacts change in width . What 's up with this ? I have no i... | import cv2cv2.imshow ( `` , image ) from matplotlib import pyplotpyplot.imshow ( image , cmap= '' gray '' ) pyplot.show ( ) | Artifacts in PyPlot vs. OpenCV imshow |
Python | How can I append or insert a class attribute into its sub-elements , but only for direct children and then to repeat it for the next class and sub-elements.In the docs it is referenced here pyquery manipulatingSampleSo for each race classappend it into its sub-elements called nomination as raceid so nomination becomesT... | > > > d = pq ( ' < html > < body > < div id= '' test '' > < a href= '' http : //python.org '' > python < /a > ! < /div > < /body > < /html > ' ) > > > p.prependTo ( d ( ' # test ' ) ) [ < p # hello.hello > ] > > > d ( ' # test ' ) .html ( ) u ' < p class= '' hello '' .. < meeting id= '' 42499 '' barriertrial= '' 0 '' v... | PyQuery How do I append and rename an element into each of its subelements |
Python | The Python Language Reference specifies object.__await__ as follows : object.__await__ ( self ) Must return an iterator . Should be used to implement awaitable objects . For instance , asyncio.Future implements this method to be compatible with the await expression.That 's it . I find this specification very vague and ... | import asyncioclass Spam : def __await__ ( self ) : yield from range ( 10 ) async def main ( ) : await Spam ( ) asyncio.run ( main ( ) ) RuntimeError : Task got bad yield : 0 | Precise specification of __await__ |
Python | For example I get following input : And I need to get following list : Here is my code , but I do n't know how to deal with minuses.warning : I can not use any libraries except re and math . | -9x+5x-2-4x+5 [ '-9x ' , '5x ' , '-2 ' , '-4x ' , ' 5 ' ] import retext = '-3x-5x+2=9x-9'text = re.split ( r'\W ' , text ) print ( text ) | How to split algebraic expressions in a string using python ? |
Python | I have a table with keywords associated with articles , looks like this : I need to get a sort of a pivot table : It means , that the pair ( A , B ) occurs in two articles ( # 1 and # 2 ) , the pair ( A , C ) occurs in just one article ( # 1 ) , etc.What is the most Pythonic way to do that ? I tried Pandas pivot tables... | article_id keyword1 A1 B1 C2 A2 B2 D3 E3 F3 D A B C D E FA - 2 1 1 0 0B - - 1 1 0 0C - - - 0 0 0D - - - - 1 1E - - - - - 1F - - - - - - | Cross tabulate counts between pairs of keywords per group with pandas |
Python | I would like to vectorize this NumPy operation : where idx contains axis-0 index to an x slice . Is there some simple way to do this ? | for j in range ( yt ) : for i in range ( xt ) : y [ j , i ] = x [ idx [ j , i ] , j , i ] | NumPy : Evaulate index array during vectorized assignment |
Python | I am trying to calculate the # of days between failures . I 'd like to know on each day in the series the # of days passed since the last failure where failure = 1 . There may be anywhere from 1 to 1500 devices.For Example , Id like my dataframe to look like this ( please pull data from url in the second code block . T... | date device failure elapsed 10/01/2015 S1F0KYCR 1 0 10/07/2015 S1F0KYCR 1 7 10/08/2015 S1F0KYCR 0 0 10/09/2015 S1F0KYCR 0 0 10/17/2015 S1F0KYCR 1 11 10/31/2015 S1F0KYCR 0 0 10/01/2015 S8KLM011 1 0 10/02/2015 S8KLM011 1 2 10/07/2015 S8KLM011 0 010/09/2015 S8KLM011 0 010/11/2015 S8KLM011 0 010/21/2015 S8KLM011 1 20 url =... | Date Difference Between Two Device Failures |
Python | Just curious if there is a way to both print and return within one function without assigning the output to variable ? Consider this code : Is there a way to reference that variable stored for the purpose of return statement ? | def secret_number ( secret_number_range ) : return random.randrange ( 1 , secret_number_range + 1 ) | Returning and printing without assigning to variable ? |
Python | I have an array , given number of items in a group and number of groups , I need to print the array cyclically in a loop.Array- [ 1,2,3,4,5,6 ] Group- 4Iterations- 7Output should be : | [ ' 1 ' , ' 2 ' , ' 3 ' , ' 4 ' ] [ ' 5 ' , ' 6 ' , ' 1 ' , ' 2 ' ] [ ' 3 ' , ' 4 ' , ' 5 ' , ' 6 ' ] [ ' 1 ' , ' 2 ' , ' 3 ' , ' 4 ' ] [ ' 5 ' , ' 6 ' , ' 1 ' , ' 2 ' ] [ ' 3 ' , ' 4 ' , ' 5 ' , ' 6 ' ] [ ' 1 ' , ' 2 ' , ' 3 ' , ' 4 ' ] | Display grouped list of items from python list cyclically |
Python | Input data is a 2D array ( timestamp , value ) pairs , ordered by timestamp : I want to find time windows where the value exceeds a threshold ( eg . > =4 ) . Seems I can do the threshold part with a boolean condition , and map back to the timestamps with np.extract ( ) : But from that I need the first and last timestam... | np.array ( [ [ 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 ] , [ 2 , 3 , 5 , 6 , 4 , 2 , 1 , 2 , 3 , 4 , 5 , 4 , 3 , 2 , 1 , 2 , 3 ] ] ) > > > a [ 1 ] > = 4array ( [ False , False , True , True , True , False , False , False , False , True , True , True , False , False , False , F... | Threshold numpy array , find windows |
Python | I have defined the following class : And the following code works : with output : But this does not : It gives the following error : Which is because the point class is being fed into the int mul function , I 'm assuming . How can I keep the definition of point contained in the Point class and still have 3*y return the... | class Point ( object ) : def __repr__ ( self ) : return `` ( `` +str ( self.x ) + '' , '' +str ( self.y ) + '' ) '' def __init__ ( self , x , y ) : self.x = x self.y = y def __add__ ( self , point ) : return Point ( self.x+point.x , self.y+point.y ) def __sub__ ( self , point ) : return Point ( self.x-point.x , self.y-... | Overiding __mul__ in two dimensional vector class to preserve commutivity |
Python | Can I implement a generic descriptor in Python in a way it will support/respect/understand inheritance hierarchy of his owners ? It should be more clear in the code : gist - almost the same code snippet on gist | from typing import ( Generic , Optional , TYPE_CHECKING , Type , TypeVar , Union , overload , ) T = TypeVar ( `` T '' , bound= '' A '' ) # noqaclass Descr ( Generic [ T ] ) : @ overload def __get__ ( self : `` Descr [ T ] '' , instance : None , owner : Type [ T ] ) - > `` Descr [ T ] '' : ... @ overload def __get__ ( s... | typing : How to bind owner class to generic descriptor ? |
Python | Running : Books.referTable being a data descriptor is not shadowed by book.__dict__ [ 'referTable ' ] : The property ( ) function is implemented as a data descriptor . Accordingly , instances can not override the behavior of a property.To shadow it , instead of property built-in descriptor i must use my own descriptor ... | class Books ( ) : def __init__ ( self ) : self.__dict__ [ 'referTable ' ] = 1 @ property def referTable ( self ) : return 2book = Books ( ) print ( book.referTable ) print ( book.__dict__ [ 'referTable ' ] ) vic @ ubuntu : ~/Desktop $ python3 test.py 21 | Built-in non-data version of property ? |
Python | The problem is a list of room numbers and guest details I ripped straight from a txt file that needs to be put into a dictionary with the room number as the keys and the details as the values.The guest list is literally a list , each item represents room number , guest name , arrival , departure dates . Rooms without a... | nlist = [ [ '101 ' ] , [ '102 ' ] , [ '103 ' ] , [ '201 ' , ' John Cleese ' , ' 5/5/12 ' , ' 5/7/12 ' ] , [ '202 ' ] , [ '203 ' , ' Eric Idle ' , ' 7/5/12 ' , ' 8/7/12 ' ] , [ '301 ' ] , [ '302 ' ] , [ '303 ' ] ] guests = { } for i in nlist : if len ( i ) == 1 : key = i [ 0 ] guests [ key ] = None else : key = i [ 0 ] ... | How do I sort a dictionary ? |
Python | This code works but I was wondering if there is a more pythonic way for writing it.word_frequency is a dictionary of lists , e.g . : Is there a more elegant way of writing this loop ? | word_frequency = { 'dogs ' : [ 1234 , 4321 ] , 'are ' : [ 9999 , 0000 ] , 'fun ' : [ 4389 , 3234 ] } vocab_frequency = [ 0 , 0 ] # stores the total times all the words used in each classfor word in word_frequency : # that is not the most elegant solution , but it works ! vocab_frequency [ 0 ] += word_frequency [ word ]... | Pythonic way of executing a loop on a dictionary of lists |
Python | I have the following directory structurewith main_code.py just importing mylib : and mylib.py just importing time : Now it turns out that mylib.py imports libs/time.py and not the built-in standard library time . Is there any way to get the 'normal ' behavior , i.e . that mylib.py imports the built-in standard library ... | main_code.pylibs/ __init__.py mylib.py time.py from libs import mylib import timeprint time | How to import standard library instead of same-named module in module path |
Python | I have an enum for which some of the members are deprecated : How do it get the following behavior : When somebody writes Foo.BAR , everything behaves normallyWhen somebody writes Foo.BAZ , a DeprecationWarning is issued using warnings.warn ( `` BAZ is deprecated '' , DeprecationWarning ) . Afterwards everything behave... | from enum import Enumclass Foo ( Enum ) : BAR = `` bar '' BAZ = `` baz '' # deprecated | How do I detect and invoke a function when a python enum member is accessed |
Python | Can someone please explain this behaviour : | > > > a = { 'hello ' : 'world ' , 'good ' : 'food ' } > > > b = [ 1,2 ] > > > b = b + aTraceback ( most recent call last ) : File `` < stdin > '' , line 1 , in < module > TypeError : can only concatenate list ( not `` dict '' ) to list > > > b += a > > > b [ 1 , 2 , 'good ' , 'hello ' ] < -- - Why do the keys get added... | Why does += operator work differently than + and assign operator for python dictionary ? |
Python | Suppose I have a dataframe of which one column is a list ( of a unknown values and length ) for example : I came across this solution but it isnt what I am looking for.How best to extract a Pandas column containing lists or tuples into multiple columnsin theory the resulting df would look likeSee above | df = pd.DataFrame ( { 'messageLabels ' : [ [ 'Good ' , 'Other ' , 'Bad ' ] , [ 'Bad ' , 'Terrible ' ] ] } ) messageLabels | Good| Other| Bad| Terrible -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- [ 'Good ' , 'Other ' , 'Bad ' ] | True| True |True| False -- -- -- -- -- -- -- -- -- ... | How do I perform One Hot Encoding on lists in a pandas column ? |
Python | In Python the symbol int is used both as a type and a built-in function . But when I use int in the REPL , or ask for its type , the REPL tells me it is a type.This is fine , but int is also a built-in function : it is listed in the table of built-in functions right in the Python documentation.Other built-in functions ... | > > > int < type 'int ' > > > > type ( int ) < type 'type ' > > > > abs < built-in function abs > > > > type ( abs ) < type 'builtin_function_or_method ' > > > > map ( int , [ `` 4 '' , `` 2 '' ] ) [ 4 , 2 ] id ( int ) | Does Python assume a symbol is a type before trying to see if it is a function ? |
Python | Now , when I enter : I get : which does n't make a whole lot of sense to me . Can anybody explain that simply ? | two_d = np.array ( [ [ 0 , 1 , 2 , 3 , 4 ] , [ 5 , 6 , 7 , 8 , 9 ] , [ 10 , 11 , 12 , 13 , 14 ] , [ 15 , 16 , 17 , 18 , 19 ] , [ 20 , 21 , 22 , 23 , 24 ] ] ) first = np.array ( ( True , True , False , False , False ) ) second = np.array ( ( False , False , False , True , True ) ) two_d [ first , second ] array ( [ 3,9 ... | Unexpected behaviour when indexing a 2D np.array with two boolean arrays |
Python | In the code below , I import a saved sparse numpy matrix , created with python , densify it , add a masking , batchnorm and dense ouptput layer to a many to one SimpleRNN . The keras sequential model works fine , however , I am unable to use shap . This is run in Jupyter lab from Winpython 3830 on a Windows 10 desktop ... | from sklearn.model_selection import train_test_splitimport tensorflow as tffrom tensorflow.keras.models import Sequentialimport tensorflow.keras.backend as Kbfrom tensorflow.keras import layersfrom tensorflow.keras.layers import BatchNormalizationfrom tensorflow import keras as Kimport numpy as npimport shapimport rand... | Error using shap with SimpleRNN sequential model |
Python | How can I write a function `` fmap '' , with this properties : ( I search a kind of `` fmap '' in haskell , but in python3 ) .I have a very ugly solution , but there is certainly a solution more pythonic and generic ? : | > > > l = [ 1 , 2 ] ; fmap ( lambda x : 2*x , l ) [ 2 , 4 ] > > > l = ( 1 , 2 ) ; fmap ( lambda x : 2*x , l ) ( 2 , 4 ) > > > l = { 1 , 2 } ; fmap ( lambda x : 2*x , l ) { 2 , 4 } def fmap ( f , container ) : t = container.__class__.__name__ g = map ( f , container ) return eval ( f '' { t } ( g ) '' ) | How can I write a function fmap that returns the same type of iterable that was inputted ? |
Python | I have a mercurial hook like so : with the code looking like this : but this hook runs on commands that use the commit logic to do something else , in my case hg shelve . is there a way to get the command that the user has input to avoid running the hook on that command ? perhaps something like this : | [ hooks ] pretxncommit.myhook = python : path/to/file : myhook def myhook ( ui , repo , **kwargs ) : # do some stuff def myhook ( ui , repo , command , **kwargs ) : if command is `` hg shelve '' return 0 # do some stuff | ignore certain mercurial commands in mercurial hook |
Python | When i changed two words in a string with other two words using re.sub i got the output . But when i tried that with numbers output is not coming correctlyi do n't know why this happens could u please tel me how to use this Thanks in advance | > > > import re > > > a='this is the string i want to change ' > > > re.sub ( ' ( .* ) is ( .* ) want ( . * ) ' , '\\1 % s\\2 % s\\3 ' % ( 'was ' , 'wanted ' ) , a ) 'this was the string i wanted to change ' > > > re.sub ( ' ( .* ) is ( .* ) want ( . * ) ' , '\\1 % s\\2 % s\\3 ' % ( 'was ' , '12345 ' ) , a ) 'this was\... | Multiple substitutions of numbers in string using regex python |
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