pre-view/CS50-raw · Datasets at Hugging Face

text stringlengths 1 81	start float64 0 10.1k	duration float64 0 24.9
is the array that's passed in.	756.47	1.46
And so we'll use that later to use this thing called reset.	757.93	4.68
And so say we wanted to every single time we added a value to this set,	762.61	3.78
we also wanted to log, hey, we added a value to this set.	766.39	4.35
So we can just start writing this method called add.	770.74	3.29
It takes a value just like any other example.	774.03	2.114
But instead of implementing add ourself, we're	776.144	1.916
just going to use the native implementation of add.	778.06	2.25
And so that's where we use super.add.	780.31	1.6
So super, again, refers to the class that we're extending.	781.91	4.57
And so when we invoke super.add, it goes ahead	786.48	2.35
and does that using the native implementation.	788.83	2.106
And then since we're going to extend it with some additional logging.	790.936	2.874
We're just going to log, hey, we added this val to the set.	793.81	3.09
And if you're not familiar with this, if you use the backticks,	796.9	3.48
you can go ahead and add variables in line, in the string,	800.38	2.85
and it'll go ahead and substitute those in.	803.23	3.28
And so you see we added a couple of other methods here.	806.51	2.36
We have to array, which is basically saying, hey, I actually want the array,	808.87	3.48
and not the set.	812.35	0.7
And so we can just return Array.from (this).	813.05	2.41
We're passing in the entire instance.	815.46	2.86
And lastly, we have a reset, which is saying, hey,	818.32	3.27
I want the original set that I had, or at least	821.59	4.71
a new set with equivalent value.	826.3	3.06
So you can return a new my set.	829.36	1.38
So notice you are referencing my set inside that class.	830.74	3.72
We want a new one, and we're going to pass in,	834.46	2.22
as the array here, the original array.	836.68	2.12
So this is an example of us extending a class that already exists.	841.65	4.6
And as you see, if we want to reference methods on that original,	846.25	4.38
we just use that super keyword.	850.63	3.48
So any questions on sets, how we define them--	854.11	3.09
or sorry, classes and how we define them, how we extend them?	857.2	4.2
So why might this be useful?	861.4	3.82
So as you guys are doing on your project,	865.22	3.5
you're keeping track of these things called to dos.	868.72	3.07
What if we actually had a class for to do?	871.79	3.59
And when you invoke this constructor on some configuration object,	875.38	4.419
what if it pulls out the text and whether it's checked or not	879.799	2.541
and stores it as part of [? its ?] class instance?	882.34	2.732
And say we want to render it to the page.	885.072	1.708
What if we could just return some HTML like this?	886.78	2.67
It would be quite handy, right?	891.699	1.291
And that actually is our next topic, react.	892.99	5.46
So react is a JavaScript library, and it allows	898.45	2.52
us to write declarative views that will react to changes in data automatically.	900.97	4.716
It allows us to abstract complex problems into smaller components,	905.686	3.754
and it allows us to write simple code that still perform it.	909.44	3.29
And so I use this word in the first bullet, declarative.	912.73	2.91
So what the heck does that mean?	915.64	2.5
So in CS50, we learned a paradigm of coding called imperative.	918.14	5.93
And today we're going to talk about declarative coding.	924.07	3.15
So the difference in imperative and declarative	927.22	2.58
is like asking the difference between how you do something	929.8	3.33
and actually what you want out of it.	933.13	3.21
So imperative programming outlines a series of steps	936.34	3.27
to get to what you want, whereas declarative,	939.61	2.94
you just say what you want.	942.55	2.2
And it's just an implementation detail on how to get it.	944.75	4.07
And so we've learned a few different languages through CS50 in this course.	948.82	3.57
A couple that come to mind are HTML and JavaScript.	952.39	4.08
So in HTML, do we tell the browser exactly how	956.47	3.48
we want to render all of these things?	959.95	3.24
Do we tell it exactly how we want the DOM to be constructed?	963.19	4.26
No, we just tell it what we want.	967.45	2.61
And so HTML is considered a declarative language, because you just say,	970.06	3.9
hey, I want this.	973.96	0.81
And browsers are in charge of just giving you what you want.	974.77	5.69
Rather, with JavaScript, as you'll see in your first project, when	980.46	2.95
you want to do anything to the DOM with JavaScript,	983.41	2.4
you tell it, oh, first get me a new element.	985.81	3.57
Call it a div.	989.38	1.41
Then do this.	990.79	1.5
Then maybe append it to the tree.	992.29	1.65
Then maybe add a class to it.	993.94	1.208
Maybe give it some inner HTML.	995.148	2.362
And so you're telling it exactly what you want and how to do it.	997.51	2.75
And so that is the more imperative way of programming.	1,000.26	4.018
So let's take this into an example.	1,007.35	1.9
Say we had a classical guitar here, and say we	1,009.25	2.95
wanted to actually create this guitar.	1,012.2	3.75
So in an imperative way, how would you describe that?	1,015.95	3.43
Well, you would say, oh, I need a head over here.	1,019.38	3.41
I need to add some pegs to it.	1,022.79	1.26
Maybe I want the neck.	1,024.05	1.47
Maybe I add some frets to that.	1,025.52	2.085
Oh, I need to create the body and attach them all and then maybe return that.	1,027.605	4.415
And what would be a more declarative way of creating the guitar?	1,032.02	3.16
You just say, I want a guitar.	1,037.96	1.8
Maybe tune the strings to this.	1,039.76	1.319
And so an example in pseudo code would be like this.	1,041.079	8.091
So say we have a guitar, and say we have some function	1,049.17	2.92
called create element, similar to what we have in the document in HTML.	1,052.09	5.86
And say we know exactly what strings we want.	1,057.95	2.3
How might we go about creating this guitar?	1,060.25	3.45
Well, first we might want to do something like let's create a head.	1,063.7	3.24
Again, telling whoever's listening exactly what we want.	1,073.15	4.7
And then maybe for 6 pegs, maybe we want to start adding pegs to that head.	1,077.85	11.63
And so now we, in a very terse manner, have a head with six pegs.	1,101.27	6.31

is the array that's passed in.

756.47

1.46

And so we'll use that later to use this thing called reset.

757.93

4.68

And so say we wanted to every single time we added a value to this set,

762.61

3.78

we also wanted to log, hey, we added a value to this set.

766.39

4.35

So we can just start writing this method called add.

770.74

3.29

It takes a value just like any other example.

774.03

2.114

But instead of implementing add ourself, we're

776.144

1.916

just going to use the native implementation of add.

778.06

2.25

And so that's where we use super.add.

780.31

1.6

So super, again, refers to the class that we're extending.

781.91

4.57

And so when we invoke super.add, it goes ahead

786.48

2.35

and does that using the native implementation.

788.83

2.106

And then since we're going to extend it with some additional logging.

790.936

2.874

We're just going to log, hey, we added this val to the set.

793.81

3.09

And if you're not familiar with this, if you use the backticks,

796.9

3.48

you can go ahead and add variables in line, in the string,

800.38

2.85

and it'll go ahead and substitute those in.

803.23

3.28

And so you see we added a couple of other methods here.

806.51

2.36

We have to array, which is basically saying, hey, I actually want the array,

808.87

3.48

and not the set.

812.35

0.7

And so we can just return Array.from (this).

813.05

2.41

We're passing in the entire instance.

815.46

2.86

And lastly, we have a reset, which is saying, hey,

818.32

3.27

I want the original set that I had, or at least

821.59

4.71

a new set with equivalent value.

826.3

3.06

So you can return a new my set.

829.36

1.38

So notice you are referencing my set inside that class.

830.74

3.72

We want a new one, and we're going to pass in,

834.46

2.22

as the array here, the original array.

836.68

2.12

So this is an example of us extending a class that already exists.

841.65

4.6

And as you see, if we want to reference methods on that original,

846.25

4.38

we just use that super keyword.

850.63

3.48

So any questions on sets, how we define them--

854.11

3.09

or sorry, classes and how we define them, how we extend them?

857.2

4.2

So why might this be useful?

861.4

3.82

So as you guys are doing on your project,

865.22

3.5

you're keeping track of these things called to dos.

868.72

3.07

What if we actually had a class for to do?

871.79

3.59

And when you invoke this constructor on some configuration object,

875.38

4.419

what if it pulls out the text and whether it's checked or not

879.799

2.541

and stores it as part of [? its ?] class instance?

882.34

2.732

And say we want to render it to the page.

885.072

1.708

What if we could just return some HTML like this?

886.78

2.67

It would be quite handy, right?

891.699

1.291

And that actually is our next topic, react.

892.99

5.46

So react is a JavaScript library, and it allows

898.45

2.52

us to write declarative views that will react to changes in data automatically.

900.97

4.716

It allows us to abstract complex problems into smaller components,

905.686

3.754

and it allows us to write simple code that still perform it.

909.44

3.29

And so I use this word in the first bullet, declarative.

912.73

2.91

So what the heck does that mean?

915.64

2.5

So in CS50, we learned a paradigm of coding called imperative.

918.14

5.93

And today we're going to talk about declarative coding.

924.07

3.15

So the difference in imperative and declarative

927.22

2.58

is like asking the difference between how you do something

929.8

3.33

and actually what you want out of it.

933.13

3.21

So imperative programming outlines a series of steps

936.34

3.27

to get to what you want, whereas declarative,

939.61

2.94

you just say what you want.

942.55

2.2

And it's just an implementation detail on how to get it.

944.75

4.07

And so we've learned a few different languages through CS50 in this course.

948.82

3.57

A couple that come to mind are HTML and JavaScript.

952.39

4.08

So in HTML, do we tell the browser exactly how

956.47

3.48

we want to render all of these things?

959.95

3.24

Do we tell it exactly how we want the DOM to be constructed?

963.19

4.26

No, we just tell it what we want.

967.45

2.61

And so HTML is considered a declarative language, because you just say,

970.06

3.9

hey, I want this.

973.96

0.81

And browsers are in charge of just giving you what you want.

974.77

5.69

Rather, with JavaScript, as you'll see in your first project, when

980.46

2.95

you want to do anything to the DOM with JavaScript,

983.41

2.4

you tell it, oh, first get me a new element.

985.81

3.57

Call it a div.

989.38

1.41

Then do this.

990.79

1.5

Then maybe append it to the tree.

992.29

1.65

Then maybe add a class to it.

993.94

1.208

Maybe give it some inner HTML.

995.148

2.362

And so you're telling it exactly what you want and how to do it.

997.51

2.75

And so that is the more imperative way of programming.

1,000.26

4.018

So let's take this into an example.

1,007.35

1.9

Say we had a classical guitar here, and say we

1,009.25

2.95

wanted to actually create this guitar.

1,012.2

3.75

So in an imperative way, how would you describe that?

1,015.95

3.43

Well, you would say, oh, I need a head over here.

1,019.38

3.41

I need to add some pegs to it.

1,022.79

1.26

Maybe I want the neck.

1,024.05

1.47

Maybe I add some frets to that.

1,025.52

2.085

Oh, I need to create the body and attach them all and then maybe return that.

1,027.605

4.415

And what would be a more declarative way of creating the guitar?

1,032.02

3.16

You just say, I want a guitar.

1,037.96

1.8

Maybe tune the strings to this.

1,039.76

1.319

And so an example in pseudo code would be like this.

1,041.079

8.091

So say we have a guitar, and say we have some function

1,049.17

2.92

called create element, similar to what we have in the document in HTML.

1,052.09

5.86

And say we know exactly what strings we want.

1,057.95

2.3

How might we go about creating this guitar?

1,060.25

3.45

Well, first we might want to do something like let's create a head.

1,063.7

3.24

Again, telling whoever's listening exactly what we want.

1,073.15

4.7

And then maybe for 6 pegs, maybe we want to start adding pegs to that head.

1,077.85

11.63

And so now we, in a very terse manner, have a head with six pegs.

1,101.27

6.31