1
00:00:00,760 --> 00:00:07,120
Let's talk about our next data structure, and this one is called a dictionary.

2
00:00:08,790 --> 00:00:13,770
In other languages, it might be called the hash table, maybe map or objects.

3
00:00:14,800 --> 00:00:22,840
In Python, we have this idea of dictionary or Python likes to call it DECT, have to make sure I pronounce

4
00:00:22,840 --> 00:00:23,460
that properly.

5
00:00:23,470 --> 00:00:28,680
That's a really hard word to say when you're recording and you're repeating it over and over anyway.

6
00:00:29,140 --> 00:00:31,210
Dictionary, what is it?

7
00:00:31,630 --> 00:00:35,650
Well, it's a data type in Python, but it's also a data structure.

8
00:00:36,250 --> 00:00:40,380
Remember that I mentioned this idea of data structure when we talked about lists.

9
00:00:40,930 --> 00:00:45,280
There were the first the data structure in Python that we learned.

10
00:00:45,730 --> 00:00:53,800
It's a way for us to organize our data in a form that is has some different pros and cons and how we

11
00:00:53,800 --> 00:00:54,340
access it.

12
00:00:54,550 --> 00:00:59,380
For example, with lists, we saw that they're easily ordered.

13
00:00:59,380 --> 00:01:02,470
We can access them through indexes like zero one.

14
00:01:02,470 --> 00:01:03,730
We can reverse them.

15
00:01:03,730 --> 00:01:04,960
We can insert into them.

16
00:01:05,170 --> 00:01:06,440
It was really, really nice.

17
00:01:06,910 --> 00:01:08,050
What about dictionaries?

18
00:01:08,800 --> 00:01:10,900
Well, let's see what a dictionary looks like.

19
00:01:11,320 --> 00:01:12,220
A dictionary.

20
00:01:14,090 --> 00:01:17,540
We'll look something like this will have a key.

21
00:01:18,590 --> 00:01:19,700
And a value.

22
00:01:20,810 --> 00:01:23,100
Then another comma and then another key.

23
00:01:24,500 --> 00:01:26,180
And another value.

24
00:01:27,590 --> 00:01:35,690
Let's decipher this, so I'm using curly brackets here, which denotes a dictionary and unlike a list,

25
00:01:35,870 --> 00:01:45,470
we have what we call a key value pair, a key is a string for us to grab the value.

26
00:01:46,670 --> 00:01:47,240
What do I mean?

27
00:01:47,540 --> 00:01:52,100
Well, in order for us to access any of these values, I would go dictionary.

28
00:01:53,530 --> 00:02:00,370
And then say the key in our case, let's say we want to grab we would grab the key and then when we

29
00:02:00,370 --> 00:02:01,990
print here the result.

30
00:02:04,730 --> 00:02:10,900
We get the value to we're essentially telling the computer, hey, I have this valuable dictionary,

31
00:02:10,910 --> 00:02:15,110
remember, I can mean this whatever I want, I have this variable dictionary.

32
00:02:15,230 --> 00:02:21,780
I want you to go find the key B and this key B if it exists, grab me the value.

33
00:02:21,830 --> 00:02:25,130
So it's going to go into your memory or into the machine's memory.

34
00:02:25,340 --> 00:02:30,310
It's going to find where B is stored in our memory and grab the value.

35
00:02:30,410 --> 00:02:37,610
So in the bookshelf, B, we have the value to what if we do see which doesn't exist.

36
00:02:37,760 --> 00:02:40,550
If I click run now I get an error.

37
00:02:40,610 --> 00:02:44,630
It tells me, hey, sorry, you're looking for Kissi, but I don't really have that key.

38
00:02:45,260 --> 00:02:47,390
And this is what a dictionary is.

39
00:02:47,690 --> 00:02:51,830
A dictionary is an unordered key value pair.

40
00:02:52,500 --> 00:02:57,860
What I mean by that unordered means that they are not right next to each other in memory.

41
00:02:58,070 --> 00:03:05,120
Remember, with lists we could access lists with index of zero, an index of one, index of two, all

42
00:03:05,120 --> 00:03:10,970
those bookshelves or right next to each other, a dictionary on the other hand, they're all over the

43
00:03:10,970 --> 00:03:11,360
place.

44
00:03:11,540 --> 00:03:17,600
Although I've put A and B here, this might be in one spot, a memory in this one, in another spot

45
00:03:17,600 --> 00:03:18,110
in memory.

46
00:03:18,830 --> 00:03:23,540
And if I added, let's say X, this will be in another spot in memory.

47
00:03:24,390 --> 00:03:27,550
And this might not be in order.

48
00:03:27,660 --> 00:03:35,250
Maybe I've written it a, B, X, but when I actually return the entire dictionary, maybe I don't have

49
00:03:35,250 --> 00:03:35,850
this in order.

50
00:03:36,210 --> 00:03:38,640
These are all just scattered all across our memory.

51
00:03:39,830 --> 00:03:45,230
As you see here, when I received the dictionary, I get these things in order, but that's only because

52
00:03:45,230 --> 00:03:45,760
it's small.

53
00:03:45,770 --> 00:03:51,350
If I had a really, really large dictionary, I might not have them in order that I've inserted it in.

54
00:03:52,450 --> 00:04:01,030
So a dictionary is an unordered key value pair, and as long as we know the key, that is whatever the

55
00:04:01,030 --> 00:04:07,300
key that we're looking for, then we just give that and our computer is going to know, hey, where

56
00:04:07,300 --> 00:04:09,730
in memory to look to grab the values.

57
00:04:10,890 --> 00:04:17,070
Now, here's the cool thing about data structures like dictionaries and lists their containers around

58
00:04:17,250 --> 00:04:18,240
data, right?

59
00:04:18,450 --> 00:04:21,360
So this can be anything that we want.

60
00:04:21,570 --> 00:04:23,820
Let's say we want this one to be a list.

61
00:04:23,820 --> 00:04:25,350
One, two, three.

62
00:04:25,800 --> 00:04:28,080
Maybe we want this to be a string.

63
00:04:28,620 --> 00:04:29,120
Hello.

64
00:04:29,460 --> 00:04:32,340
And maybe this is a boolean value like.

65
00:04:32,340 --> 00:04:32,760
True.

66
00:04:33,960 --> 00:04:38,870
That is completely valid, I can access the A.

67
00:04:40,030 --> 00:04:46,960
Like, so and I get the list, what if I want the second item in the list while I do index of one like

68
00:04:46,960 --> 00:04:47,290
this?

69
00:04:49,480 --> 00:04:56,050
And there you go, I get to and this is the same with lists and you'll see this a lot, where if we

70
00:04:56,050 --> 00:05:06,460
had a list or let's call it my list and my list contains a dictionary that has, let's say a.

71
00:05:08,030 --> 00:05:08,660
One.

72
00:05:09,730 --> 00:05:12,850
And you know what, let's just copy and paste this, we'll do this.

73
00:05:14,190 --> 00:05:16,290
So we'll have the first item in the array.

74
00:05:19,200 --> 00:05:23,040
Like this, then comma, then another item in the array.

75
00:05:25,290 --> 00:05:28,920
And this time around, this one has four, five, six.

76
00:05:30,660 --> 00:05:33,420
So that I can now grab from my list.

77
00:05:37,110 --> 00:05:38,610
First item.

78
00:05:39,890 --> 00:05:40,580
Indira.

79
00:05:42,080 --> 00:05:44,030
And then maybe grab.

80
00:05:45,360 --> 00:05:52,950
The A that is the akey, so remember, this is a string and that we want to grab, let's say, the third

81
00:05:52,980 --> 00:05:54,660
item, so we'll go.

82
00:05:56,590 --> 00:06:00,970
To fight run this, I should get three and two.

83
00:06:02,230 --> 00:06:02,750
There you go.

84
00:06:03,580 --> 00:06:08,800
Now, you might be asking yourself, hmm, what's the deal with these data structures?

85
00:06:08,800 --> 00:06:10,740
Like, why do we need a dictionary?

86
00:06:10,750 --> 00:06:12,280
Why do we need a list?

87
00:06:12,280 --> 00:06:14,250
Why can we just have one thing that does everything?

88
00:06:14,260 --> 00:06:15,400
Isn't that simpler?

89
00:06:16,300 --> 00:06:20,140
Think about that, because in the next video, I'm going to try and answer that question for you.