1
00:00:00,940 --> 00:00:07,270
It's time to talk about another topic that sounds a lot more confusing, Short-circuiting than it actually

2
00:00:07,270 --> 00:00:07,500
is.

3
00:00:07,510 --> 00:00:08,920
It's quite simple.

4
00:00:10,420 --> 00:00:16,870
Short-circuiting looks something like this, remember when I taught you the word and so we can use,

5
00:00:17,560 --> 00:00:20,500
let's say, for example, is friend?

6
00:00:23,090 --> 00:00:31,080
He calls the true and let's say is user xcode the true?

7
00:00:32,170 --> 00:00:39,460
And I can do an expression here saying is a friend and is user.

8
00:00:41,890 --> 00:00:47,020
Now, in here, when we run this, let's print it here just so we can see.

9
00:00:48,390 --> 00:00:49,710
If I run this.

10
00:00:50,750 --> 00:00:55,460
I get true because both of these evaluate to true.

11
00:00:56,560 --> 00:01:03,040
So that if I had this as an F block, let's say, if it was if his friend and is user.

12
00:01:04,150 --> 00:01:04,640
Print.

13
00:01:05,530 --> 00:01:07,690
Best friends forever.

14
00:01:09,300 --> 00:01:18,510
Now, short circuiting can be done when we use something like four, which we haven't seen before,

15
00:01:18,510 --> 00:01:21,560
but again, you can see here that it's highlighted in blue.

16
00:01:21,570 --> 00:01:30,180
So it is a key word, a python key word now or says if either one of these conditions are true, then

17
00:01:30,180 --> 00:01:32,230
run this piece of code.

18
00:01:32,730 --> 00:01:34,050
So if I run this.

19
00:01:35,220 --> 00:01:37,200
I get best friends forever.

20
00:01:38,760 --> 00:01:45,570
Now, let me ask you this, which operation do you think is more performant the or or the end?

21
00:01:46,080 --> 00:01:47,010
Is there a difference?

22
00:01:48,130 --> 00:01:55,930
As a matter of fact, there is because of short circuiting, you see, when I do or hear, because I

23
00:01:55,930 --> 00:01:58,810
only care if either one of this is true.

24
00:01:59,890 --> 00:02:02,290
The Python interpreter is going to say if.

25
00:02:03,370 --> 00:02:09,790
Is friend, and it's going to evaluate that and say, oh, this is this is true, and then it's going

26
00:02:09,790 --> 00:02:14,560
to see the word or and it's going to say, hey, I don't care what this is.

27
00:02:14,590 --> 00:02:18,910
Maybe this is a really heavy operation or something that I need to look up.

28
00:02:19,130 --> 00:02:22,060
Well, I don't really care because this is already true.

29
00:02:22,060 --> 00:02:28,240
Whether this is true or this is false, I don't really care, because either way, I'm going to have

30
00:02:28,240 --> 00:02:28,900
to print this.

31
00:02:29,290 --> 00:02:32,710
As you can see, it's still prints best friends forever.

32
00:02:33,920 --> 00:02:40,970
So Short-circuiting happens when the interpreter is smart enough to say, I already did enough work,

33
00:02:40,970 --> 00:02:44,030
I don't care what this is, this is just wasted work if I do it.

34
00:02:44,030 --> 00:02:50,300
So I'm going to short circuit and say, hey, I'm going to just ignore this and I'm going to start printing.

35
00:02:51,020 --> 00:02:54,460
So using or is a little bit more efficient.

36
00:02:54,590 --> 00:02:56,780
But again, it depends on what you need.

37
00:02:57,200 --> 00:03:03,110
If you need to check if both its friend and is users true, you'll have to use and.

38
00:03:04,600 --> 00:03:07,480
But this works both ways with and as well.

39
00:03:07,930 --> 00:03:15,940
For example, if its friend is false, this is going to get short circuited because I'm going to say,

40
00:03:15,940 --> 00:03:23,770
hey, if its friend is false, well, I don't really care what is user is, because there's no way that

41
00:03:23,770 --> 00:03:24,760
both of these are true.

42
00:03:24,790 --> 00:03:26,670
I've already seen that one of them is false.

43
00:03:26,920 --> 00:03:30,610
So I'm going to ignore this and I'm going to print this.

44
00:03:30,730 --> 00:03:34,660
And when I say I, I mean our good old friend, Python interpreter.

45
00:03:35,810 --> 00:03:42,650
Now, this topic of short circuiting doesn't really get taught in beginner python courses, but now

46
00:03:42,650 --> 00:03:45,110
if you hear this, maybe you hear this in an interview.

47
00:03:45,660 --> 00:03:50,390
As you can see, it sounds a lot more difficult than it actually is.

48
00:03:50,390 --> 00:03:52,960
And frankly, it makes a lot of sense.

49
00:03:52,970 --> 00:03:53,170
Right.

50
00:03:53,780 --> 00:03:59,050
We want our machines to be efficient and it is quite efficient due to short circuiting.

51
00:03:59,900 --> 00:04:01,700
I'll see in the next one by.