WEBVTT 00:00.050 --> 00:05.030 You can now use conditions to test some variables and test if something is true or false. 00:05.060 --> 00:11.630 Now let's see what are the different comparison operators which will allow you to test different things. 00:11.660 --> 00:13.310 Okay, so comparison operator. 00:13.310 --> 00:15.440 For now we have only seen that one. 00:15.440 --> 00:18.470 And we are going to discover all of them right now. 00:18.560 --> 00:22.520 So first of all I will actually comment. 00:23.030 --> 00:24.260 I'm going to keep the same file. 00:24.260 --> 00:25.580 I will comment those lines. 00:25.580 --> 00:27.740 So if you want to comment you just select. 00:27.770 --> 00:32.120 You can right click for example and click on Toggle comment. 00:32.120 --> 00:33.980 And you have the shortcut if you want to. 00:34.310 --> 00:37.190 And I'm going to write some code here at the top. 00:37.190 --> 00:39.140 So I will create a simple variable. 00:39.140 --> 00:42.530 Let's name it a just for testing purposes. 00:42.740 --> 00:44.510 And let's say A is equal to five. 00:44.510 --> 00:46.940 And then let's do let's do a condition. 00:46.940 --> 00:51.350 So if A is greater than three. 00:51.920 --> 00:53.360 So same condition as before. 00:53.360 --> 00:58.460 With this symbol we use the if and then a condition colon. 00:58.460 --> 01:01.790 We go back to new line let's say print okay. 01:01.940 --> 01:05.180 So let's run this we have. 01:05.210 --> 01:05.600 Okay. 01:05.630 --> 01:07.280 Because five is greater than three. 01:07.280 --> 01:11.030 So this is the first operator is greater than three. 01:11.030 --> 01:12.740 And actually I mentioned it before. 01:12.740 --> 01:14.900 It's strictly greater than three. 01:14.900 --> 01:20.570 So if I put three for example you will see that we don't have okay. 01:20.570 --> 01:25.550 So three is not strictly greater than three okay. 01:25.580 --> 01:31.490 For this to be true A needs to be at least at least four okay. 01:31.490 --> 01:32.630 Then it's going to work. 01:32.660 --> 01:34.220 You see now we have okay. 01:34.250 --> 01:34.820 All right. 01:34.820 --> 01:42.500 So with this angle bracket it means strictly greater than if you want to test if something is greater 01:42.500 --> 01:45.470 or equal then you can add an equal sign okay. 01:45.470 --> 01:47.360 Greater or equal. 01:47.450 --> 01:51.050 In this case well four is still greater or equal than three. 01:51.080 --> 01:58.400 But then three is also going to work because three is greater or equal than three okay. 01:58.430 --> 02:00.350 So note this small difference. 02:00.380 --> 02:02.780 It's actually quite important difference. 02:03.260 --> 02:07.040 It's strictly greater or greater or equal then. 02:07.070 --> 02:08.510 Now you can do the opposite. 02:08.510 --> 02:11.120 So we have greater but you have lower. 02:11.120 --> 02:15.620 So we have this symbol for greater and this symbol for lower. 02:15.620 --> 02:18.560 And this one is actually going to be strictly lower. 02:18.560 --> 02:21.920 So with three you see it's not going to work. 02:21.980 --> 02:26.720 But if I put one one is strictly lower than three. 02:26.720 --> 02:27.740 So it works. 02:27.740 --> 02:30.530 And I also have lower or equal. 02:30.530 --> 02:32.450 So it still works with one. 02:32.570 --> 02:40.190 And if I put back three we have three is lower or equal than three. 02:40.220 --> 02:43.130 So this condition is true okay. 02:43.160 --> 02:45.560 So you already have four operators. 02:45.560 --> 02:51.230 Now if we want to test the equality we can use equal equal sign. 02:51.260 --> 02:55.430 This is going to test if A is equal to three okay. 02:55.460 --> 03:01.760 So the only way this condition is true is if A is exactly three like this one you can see okay. 03:01.760 --> 03:06.230 But if I put any other value like four doesn't work. 03:06.440 --> 03:08.060 Two it doesn't work. 03:08.060 --> 03:09.320 Well I think you get it. 03:09.320 --> 03:12.200 So this will test the equality. 03:12.350 --> 03:17.930 And note that it is super important to have two equal signs. 03:17.960 --> 03:18.320 Okay. 03:18.350 --> 03:20.090 This is a very common mistake. 03:20.120 --> 03:22.550 You write a condition and you just write this. 03:22.580 --> 03:23.120 Okay. 03:23.150 --> 03:29.300 It looks like it makes sense and you can run it and well you will see that you get an error. 03:29.330 --> 03:33.530 At least you get an error, because in some other languages, you might not even get an error. 03:33.530 --> 03:35.930 And this will be very hard to debug. 03:35.930 --> 03:40.100 So make sure that when you test the equality you have two equal signs okay? 03:40.130 --> 03:46.490 One equal sign is already used to assign a value to a variable okay. 03:46.520 --> 03:50.870 So two equal sign is the comparison operator for equality. 03:50.870 --> 03:52.550 And now if you want to test the opposite. 03:52.550 --> 04:00.230 So if you want to test if something is different than something else you can use exclamation mark equal. 04:00.230 --> 04:04.340 In this case this is going to be true if a is different than three. 04:04.340 --> 04:10.850 So any other value here you can see two is going to work because two is different than three. 04:10.940 --> 04:17.180 Then if I put three This is false because well three is equal to three. 04:17.180 --> 04:18.440 So it's not different. 04:18.470 --> 04:18.860 All right. 04:18.860 --> 04:21.410 So with this you have seen all of the operators. 04:21.410 --> 04:24.980 So we have seen the greater the greater or equal. 04:25.310 --> 04:28.220 So that one we have also seen the lower. 04:28.220 --> 04:34.670 So strictly lower lower or equal we have seen the equal with two equal signs. 04:34.670 --> 04:39.230 And then the different than with exclamation mark equal. 04:39.230 --> 04:43.610 So those are the six operators that you can use in Python. 04:44.840 --> 04:50.150 And on top of that you can actually combine different conditions. 04:50.180 --> 04:52.880 Because here we just have one condition. 04:52.880 --> 04:57.980 But maybe you want to test a combination of two different conditions or a combination of five conditions. 04:57.980 --> 04:59.390 Then you can use the keywords. 04:59.390 --> 05:00.470 So we have two keywords. 05:00.470 --> 05:02.690 We have the keywords or like this. 05:02.690 --> 05:04.820 And we have the keyword end. 05:04.850 --> 05:07.370 And you can see we have syntax highlighting for those. 05:07.370 --> 05:10.100 Let me make an example and you will understand. 05:10.100 --> 05:16.750 So if I want to test that for example A is greater or equal than 20. 05:16.750 --> 05:21.640 And I want to make sure that A is greater or equal than 20, but that A is also lower than 30. 05:21.670 --> 05:24.730 So what I can do is to use the end keyword. 05:24.730 --> 05:26.200 And I can put two conditions. 05:26.200 --> 05:29.230 So a strictly lower than 30 for example. 05:29.260 --> 05:30.550 Now let's run this. 05:31.450 --> 05:33.010 You can see that we don't have. 05:33.040 --> 05:33.550 Okay. 05:33.580 --> 05:39.160 Now if I put uh 24 for example this is going to be okay. 05:39.160 --> 05:43.180 So what happens in this case with the end keyword. 05:43.180 --> 05:46.570 Well simply this is going to be true. 05:46.570 --> 05:49.960 So we are only going to execute the if so the block of code here. 05:49.990 --> 05:54.850 If that condition is true and that condition is true. 05:54.850 --> 06:00.130 So both conditions need to be true so that we can print okay. 06:00.130 --> 06:04.900 So in this case with 24 is 24 greater or equal than 20. 06:04.900 --> 06:05.350 Yes. 06:05.350 --> 06:09.010 And is 24 strictly lower than 30. 06:09.040 --> 06:09.820 Yes. 06:09.820 --> 06:11.140 So we print okay. 06:11.170 --> 06:13.780 Now let's say I use 30. 06:13.900 --> 06:16.180 Then we are not going to print okay. 06:16.330 --> 06:17.650 Because this one is true. 06:17.650 --> 06:23.020 So 30 is greater than 20, but then 30 is not strictly greater than 30. 06:23.020 --> 06:28.630 So because we have true and false, the whole thing becomes false. 06:28.660 --> 06:29.020 Okay. 06:29.020 --> 06:30.730 So that's how you use the end keyword. 06:30.730 --> 06:34.870 And we're going to see more examples of that as we progress throughout the course. 06:35.260 --> 06:37.510 And now let's make an example with the Or. 06:37.540 --> 06:39.460 So I'm going to test a different use case. 06:39.580 --> 06:48.070 Let's say I have a is equal to ten or a is equal to 20. 06:48.100 --> 06:53.860 So in this case I just want to test that a is either 10 or 20. 06:53.890 --> 06:59.110 So if I put a ten here this is going to work. 06:59.110 --> 07:00.670 This is going to be okay. 07:00.940 --> 07:05.020 If I put a zero it's not going to work. 07:05.050 --> 07:05.650 Okay. 07:06.040 --> 07:09.160 So any other value than 10 or 20 is not going to work. 07:09.460 --> 07:10.900 If I put 20 it's working. 07:10.900 --> 07:12.670 So how does that work. 07:12.670 --> 07:18.580 So with the all keyword you just need to have one condition to be true so that the whole thing will 07:18.580 --> 07:19.090 be true. 07:19.120 --> 07:19.330 Okay. 07:19.360 --> 07:21.250 That's the difference with the in keyword. 07:21.310 --> 07:27.910 So for example here with a is equal to 20 we check the first condition is a is equal to ten. 07:27.940 --> 07:29.500 No this is false. 07:29.500 --> 07:30.040 We go to. 07:30.070 --> 07:32.170 The second one is a is equal to 20. 07:32.200 --> 07:32.800 Yes. 07:32.800 --> 07:35.830 So because this one is true the whole thing becomes true. 07:35.830 --> 07:39.790 And we enter the if and you can also combine more than two conditions. 07:40.000 --> 07:44.440 You can use any combination of all keyword and end keyword as you want. 07:44.470 --> 07:50.770 Let's just add another or here A is equal to 30 okay. 07:50.770 --> 07:55.300 So in this case it still works because this one is going to be false. 07:55.330 --> 07:56.980 This one is going to be true. 07:57.010 --> 07:58.390 This one is going to be false. 07:58.390 --> 08:03.070 But because we are using or we just need one of them to be true okay. 08:03.100 --> 08:07.900 So if I put 30 that's also going to be true okay. 08:07.900 --> 08:09.370 Because this is false. 08:09.400 --> 08:12.310 This is false and this one is true. 08:12.310 --> 08:13.990 So the whole thing becomes true. 08:14.440 --> 08:14.860 All right. 08:14.860 --> 08:19.750 So now you have seen the six comparison operators and you have seen the keywords or and the keywords. 08:19.750 --> 08:23.170 And so that you can combine different conditions. 08:23.170 --> 08:25.540 Now let's do a bit more practice.