WEBVTT 00:00.050 --> 00:05.930 This is the solution for the activity number two, where you have to validate the user input. 00:05.930 --> 00:07.910 And I already gave to you. 00:07.940 --> 00:09.440 Well the function input. 00:09.440 --> 00:11.270 So you can get the user input. 00:11.270 --> 00:14.330 And also how to cast it into an integer. 00:14.360 --> 00:16.310 Just one thing I'm going to run this. 00:16.310 --> 00:19.850 And what I can provide a number any number is going to work. 00:19.850 --> 00:22.910 But let's say I provide a string. 00:22.940 --> 00:28.760 You will see that we get an error because we cannot cast a string to an integer. 00:28.760 --> 00:34.310 So already with this program, we are sure that whatever is after line one is going to be an integer 00:34.310 --> 00:34.880 number. 00:34.880 --> 00:43.340 And now I'm just going to save this as activity two dot p y. 00:44.240 --> 00:45.980 So let's save the file. 00:46.340 --> 00:46.610 Okay. 00:46.640 --> 00:49.220 So you will be able to download this file as well. 00:49.220 --> 00:51.980 And let's write our condition here. 00:51.980 --> 00:53.090 So we have a number. 00:53.120 --> 00:56.420 How do we validate that it's between 1 and 100. 00:56.420 --> 00:58.130 So there are actually two ways to do that. 00:58.130 --> 01:01.540 You can either check if it's between 1 and 100. 01:01.570 --> 01:05.740 Or you can check if it's actually lower than zero or greater than 100. 01:05.770 --> 01:05.950 Okay. 01:05.980 --> 01:12.310 When you want to validate a user input, you can check if it's correct or you can check if it's wrong. 01:12.310 --> 01:15.310 And usually we're going to check if it's wrong first. 01:15.310 --> 01:17.110 So there are many examples of that. 01:17.110 --> 01:23.200 For example, if you if you go online, you create a new account in a website and you need to set up 01:23.200 --> 01:27.880 a password that's at least, for example, 10 or 12 characters. 01:27.880 --> 01:33.940 Usually what you will see is that if the password is less than 12 characters, you will get a message 01:33.940 --> 01:37.330 saying the password needs to be at least 12 characters. 01:37.330 --> 01:38.140 So you get an error. 01:38.170 --> 01:42.820 You get a message to tell you that the length of the password is wrong, but they don't really tell 01:42.820 --> 01:43.360 you anything. 01:43.390 --> 01:46.150 If the password is 14 or 15 or 20 characters. 01:46.180 --> 01:51.340 Okay, the important thing is just to make sure that the length of the password is not wrong. 01:51.370 --> 01:57.460 Okay, so you can see very often to validate that the user input is correct, we actually verify that 01:57.460 --> 01:59.590 it is not wrong okay. 01:59.620 --> 02:01.110 And that's what we're going to do here. 02:01.110 --> 02:02.520 I'm going to do if. 02:02.760 --> 02:06.090 So we want the number to be minimum one. 02:06.090 --> 02:15.810 So I can say that if the number is lower or equal than zero, or if the number is greater strictly than 02:15.810 --> 02:20.340 100, then the number is wrong. 02:20.370 --> 02:20.700 Okay. 02:20.730 --> 02:27.780 So once again if the number you provide is zero or less, we are already out of the valid range. 02:27.780 --> 02:34.290 Then if the number is greater, so strictly greater than 100 because 100 is valid, then we are also 02:34.290 --> 02:37.050 out of the range of accepted values. 02:37.260 --> 02:37.680 Okay. 02:37.680 --> 02:43.770 So with the combination of those two conditions here with the Or keyword, we check if this is true. 02:44.070 --> 02:49.020 So for example if number is minus one then well this is going to be true. 02:49.020 --> 02:52.020 And then if the number is well greater than zero. 02:52.020 --> 02:55.980 But if it's also greater than 100 this is going to be true. 02:56.100 --> 03:00.240 So we can print wrong number. 03:01.430 --> 03:04.280 So wrong number. 03:05.600 --> 03:07.310 And actually let's print. 03:07.520 --> 03:08.600 Let's print the number. 03:08.600 --> 03:09.110 So. 03:09.140 --> 03:13.430 To concatenate two strings you can do plus okay. 03:13.460 --> 03:16.160 And number this is going to give us an error. 03:16.190 --> 03:17.750 I'm just going to come back in a minute. 03:17.750 --> 03:22.130 And just to note here is I have used the lower or equal than zero. 03:22.160 --> 03:25.430 I could have used strictly lower than one. 03:25.460 --> 03:25.820 Okay. 03:25.850 --> 03:29.450 You would have also worked here for integers. 03:29.480 --> 03:31.610 I'm just going to keep this one. 03:31.700 --> 03:33.860 And so let's actually try this. 03:33.860 --> 03:36.530 Let's try this with a wrong number. 03:36.800 --> 03:39.710 So enter a number between 1 and 100. 03:39.710 --> 03:42.260 Let's say I put 200. 03:42.710 --> 03:44.180 Let's see what we have. 03:44.210 --> 03:54.470 Well we have an error because you can see on line four you can only concatenate string with string not 03:54.470 --> 03:55.340 integers. 03:55.340 --> 03:56.510 Why we have this error. 03:56.510 --> 03:58.430 Because now number is an integer. 03:58.430 --> 04:00.140 We just cast it to an integer. 04:00.170 --> 04:03.320 Now it says that you can only concatenate string with string. 04:03.320 --> 04:04.910 So this is a string. 04:05.270 --> 04:06.860 This is an integer. 04:06.860 --> 04:08.870 So that's that's a problem. 04:08.870 --> 04:10.070 How do we fix this. 04:10.070 --> 04:13.400 Well we can cast this integer to a string. 04:13.400 --> 04:16.400 So we do str number. 04:16.400 --> 04:22.220 So basically we cast back the number to a string and make sure you add the correct amount of parentheses. 04:22.250 --> 04:22.940 All right. 04:22.970 --> 04:26.960 So we have a string plus a string. 04:26.990 --> 04:29.270 Let's run again. 04:29.270 --> 04:31.310 And let's put 200 again. 04:31.400 --> 04:34.370 You can see wrong number 200. 04:34.640 --> 04:36.710 Now if I put a correct number. 04:36.710 --> 04:39.830 So let's say one one should work. 04:39.860 --> 04:42.050 You can see we don't print anything. 04:42.050 --> 04:44.300 So maybe we could say that it's correct. 04:44.300 --> 04:45.800 So how do we do this. 04:45.830 --> 04:51.320 We just create an else block print correct number. 04:55.280 --> 04:57.920 You could also print the number again if you want. 04:57.950 --> 04:59.900 Now let's run again. 04:59.900 --> 05:03.520 So enter a number between 1 and 101. 05:03.550 --> 05:05.170 You can see the correct number. 05:05.170 --> 05:06.850 We have validated the number. 05:07.000 --> 05:09.610 Let's run again with. 05:09.700 --> 05:13.180 Let's test the edge cases. 05:13.180 --> 05:16.420 So 100 100 is the correct number. 05:16.450 --> 05:17.110 Okay. 05:17.380 --> 05:22.810 Now for example if I put zero or if I put minus one you see wrong number. 05:22.840 --> 05:23.260 Great. 05:23.260 --> 05:26.470 And we have successfully validated the user input. 05:26.470 --> 05:28.060 And as an additional challenge. 05:28.060 --> 05:29.710 So I'm not going to give you the solution here. 05:29.710 --> 05:31.750 But you could do the opposite. 05:31.750 --> 05:36.370 So instead of checking if it's wrong you will check if it's true. 05:36.370 --> 05:43.060 And for this you will also need to combine two conditions with the statement and keyword. 05:43.090 --> 05:43.390 Okay. 05:43.420 --> 05:49.210 And you can easily test actually if your code is working, because when you put a number between 1 and 05:49.210 --> 05:51.760 100, you should see that it's a correct number. 05:51.790 --> 05:52.120 All right. 05:52.120 --> 05:56.860 But that's if you want to do additional practice with conditions then you can continue with loops. 05:56.860 --> 06:01.540 And we are getting close to the end for the Python basics for this course.