WEBVTT 00:00.080 --> 00:02.870 This is the solution for the activity number three. 00:02.870 --> 00:08.420 And in this activity you had to compute the max value from a number list. 00:08.420 --> 00:13.010 So as a first step you just write the code here and as a second step with a function. 00:13.010 --> 00:13.820 So let's do that. 00:13.820 --> 00:15.050 Let's start with the first step. 00:15.050 --> 00:16.460 We have our list. 00:16.520 --> 00:22.790 I have already created a variable here max value that I initialize to what I need to initialize it with 00:22.790 --> 00:23.300 something. 00:23.300 --> 00:23.810 So. 00:23.840 --> 00:25.790 So the first element of the list. 00:25.820 --> 00:32.540 Now to be able to find the max value from this list, I will need to basically go through each element. 00:32.570 --> 00:35.090 To go through each element I will use a for loop. 00:35.090 --> 00:39.170 So for number because it's the number list, we use number. 00:39.200 --> 00:44.420 In number list I put a colon and I go to a new line. 00:44.420 --> 00:46.670 Now what do I do with each element. 00:46.670 --> 00:53.630 Well I will simply compare that element with the current value that we have inside the max value variable. 00:53.630 --> 01:03.420 So I can put an if here, and if I find that the number is greater strictly than the max value. 01:04.260 --> 01:07.530 Then it means that I have found a new maximum. 01:07.530 --> 01:12.570 So then I can say that the max value is equal to the number. 01:12.960 --> 01:15.690 And that's how we find our max value. 01:15.690 --> 01:17.730 And that's all the code that you need. 01:17.760 --> 01:17.910 Okay. 01:17.940 --> 01:21.540 So let's go back to this with a bit more explanation. 01:21.540 --> 01:23.430 If you didn't manage to get this. 01:23.430 --> 01:25.110 So we go through each element. 01:25.110 --> 01:27.240 And so for example for the first element. 01:27.240 --> 01:30.120 So we're going to go to the first element we're going to compare. 01:30.120 --> 01:33.900 If so number variable is going to be equal to that element. 01:33.930 --> 01:37.020 Max value is one at this point okay. 01:37.050 --> 01:39.960 So is one strictly greater than one. 01:39.960 --> 01:40.410 No. 01:40.410 --> 01:41.520 So we don't enter this. 01:41.550 --> 01:46.260 If so for the first element of course that's obvious because it's already this value. 01:46.260 --> 01:49.800 But then we go to the second element which is five. 01:49.800 --> 01:57.120 So is here five strictly greater than one which is the current max value. 01:57.180 --> 01:57.930 Yes. 01:57.930 --> 02:03.150 So in this case we enter the if and we say that the max value is now five. 02:03.180 --> 02:07.800 After this we go back actually to the four because we still have elements in the list. 02:07.830 --> 02:09.900 We go to minus six. 02:09.900 --> 02:14.400 So is minus six strictly greater than five. 02:14.430 --> 02:15.930 Because now max value is five. 02:15.960 --> 02:16.800 Well no. 02:16.800 --> 02:19.680 So we don't enter the if then we go with 12. 02:19.710 --> 02:21.990 Is 12 greater strictly than five? 02:22.020 --> 02:22.560 Yes. 02:22.560 --> 02:24.900 So now the max value is 12. 02:24.900 --> 02:26.700 And finally we do it with seven. 02:26.700 --> 02:29.490 Is seven strictly greater than 12. 02:29.520 --> 02:30.120 No. 02:30.120 --> 02:34.950 So we don't enter the if and after that we exit from the four. 02:34.950 --> 02:41.490 So I'm going to go back to indentation and print the max value. 02:42.030 --> 02:44.010 And let's run that. 02:45.270 --> 02:47.340 And the max value is 12. 02:47.550 --> 02:47.790 Okay. 02:47.820 --> 02:48.870 That's that one. 02:48.900 --> 02:49.260 Okay. 02:49.290 --> 02:54.270 And one thing that you can notice here that I talked about, but here we really do it is that well you 02:54.270 --> 03:01.870 can combine any for and if so, basically any loop and condition, you can combine them inside other 03:01.870 --> 03:02.260 ones. 03:02.290 --> 03:02.500 Okay. 03:02.530 --> 03:04.870 So here we have an if inside the for. 03:04.930 --> 03:09.490 And then you see we have a block of code inside the if you can add another if and for etc.. 03:09.520 --> 03:09.700 Okay. 03:09.730 --> 03:13.000 Just make sure that you have the correct indentation. 03:13.000 --> 03:20.920 Because if for example that one is here, then that line is not in the if it's going to be directly 03:20.920 --> 03:22.540 executed in the for. 03:22.570 --> 03:25.090 So you want that to be inside the if. 03:25.210 --> 03:25.420 Okay. 03:25.450 --> 03:30.160 So for each new block of code inside the loop or condition you add a new indentation. 03:30.160 --> 03:33.550 So here we have four spaces plus four spaces. 03:33.580 --> 03:34.030 Great. 03:34.030 --> 03:37.420 And now what we can do is create a function. 03:37.420 --> 03:41.980 Because what we did here is we got the max value from a number list. 03:41.980 --> 03:45.370 But what if you want to do that again with another list. 03:45.400 --> 03:45.610 Okay. 03:45.640 --> 03:46.180 In your program. 03:46.180 --> 03:50.020 So what if you want to do this several times we can create a function to do that. 03:50.020 --> 03:56.510 So I'm gonna I'm gonna write stuff at the beginning of the file here because you should first define 03:56.510 --> 03:57.800 a function and then use it. 03:57.800 --> 03:58.490 So let's do that. 03:58.490 --> 04:02.420 At the beginning of the program I'm going to use the def keyword. 04:02.420 --> 04:04.070 And then what do we want to do. 04:04.100 --> 04:07.820 Well we want to get the max value from a number list. 04:07.820 --> 04:15.560 So let's just write get max value from number list. 04:16.190 --> 04:20.120 It's not the smallest name, but it's very explicit. 04:20.120 --> 04:26.990 And I prefer to write explicit names than try to find very short combination of words or letters that 04:26.990 --> 04:28.490 in the end are confusing. 04:28.490 --> 04:33.350 So get max value from number list and we get a number list as a parameter. 04:33.350 --> 04:36.530 That's going to be the list that we're going to work with. 04:36.530 --> 04:38.930 So I put the colon and then I go back to a new line. 04:38.930 --> 04:40.400 I have an indentation. 04:40.400 --> 04:42.890 And what do I do in this function. 04:42.890 --> 04:44.810 Well I do exactly what I did here. 04:44.810 --> 04:48.110 I need to go through this number list. 04:48.110 --> 04:53.820 So first I have to put a max value and then go through all the elements of the number list, find the 04:53.820 --> 04:55.530 max value and return it. 04:55.560 --> 04:58.320 So I'm just going to copy this code here. 04:59.670 --> 05:03.570 So copy and paste inside the function. 05:03.990 --> 05:07.080 So for example you can see it's like this. 05:07.080 --> 05:10.350 But because it's in the function I need to add another indentation. 05:10.350 --> 05:12.870 So here I select everything and I press tab. 05:12.870 --> 05:15.060 And I'm just going to remove this space here. 05:15.330 --> 05:18.720 You can add as many spaces as you want but I'm just going to remove the space. 05:18.720 --> 05:24.570 So now you can see that for example this instruction here has four spaces here plus four plus four because 05:24.570 --> 05:26.310 we have one two and three indentation. 05:26.310 --> 05:29.400 So in this function we receive a parameter that's number list. 05:29.400 --> 05:30.990 That's going to be local variable. 05:30.990 --> 05:33.810 Inside this function we set an initial value. 05:33.810 --> 05:35.190 And then we compute. 05:35.220 --> 05:38.850 Well we use this for loop that I just described to get the max value. 05:38.850 --> 05:40.680 But then that's not it. 05:40.710 --> 05:43.530 We need to return this max value. 05:43.530 --> 05:45.360 So I'm going back to a new line. 05:45.360 --> 05:53.350 And I need to go back to indentations here to be On that level and I can do return. 05:53.500 --> 05:55.390 Max value. 05:55.420 --> 05:55.780 Okay. 05:55.810 --> 06:00.730 It's very important to write the return here because if you do that the return is going to be inside 06:00.730 --> 06:01.570 the for loop. 06:01.570 --> 06:07.000 So after we check the first element we are going to already return from the function and not check the 06:07.000 --> 06:08.590 other elements okay. 06:08.620 --> 06:13.750 And if I do this, then as soon as we enter the if we are going to return from the function. 06:13.750 --> 06:20.500 So you have the return exactly at this indentation and also not here because there it will be invalid 06:20.530 --> 06:22.960 because this is the return outside of the function. 06:22.990 --> 06:23.200 Okay. 06:23.230 --> 06:26.650 So exactly here with this indentation. 06:26.680 --> 06:27.220 Great. 06:27.220 --> 06:30.910 And so now let's just remove that code here. 06:30.910 --> 06:32.380 We don't need it anymore. 06:33.070 --> 06:37.570 I have my list and I can do max value is equal to. 06:37.600 --> 06:43.960 And then instead of doing all the computation again I just call the function get max value. 06:43.960 --> 06:47.230 And actually, as I told you before you can use the auto completion. 06:47.230 --> 06:54.130 So here with Tony you press Ctrl space and you have a suggestion, then you can press Tab or enter to 06:54.160 --> 06:55.570 accept this. 06:55.570 --> 06:59.530 And you already have the name and you're going to pass the number list. 07:00.880 --> 07:03.490 Close the parentheses okay. 07:03.730 --> 07:05.650 Let's just remove the space here. 07:05.710 --> 07:07.120 Make it a bit cleaner. 07:07.120 --> 07:08.500 So we create a number list. 07:08.530 --> 07:09.490 We call the function. 07:09.490 --> 07:12.310 We pass the number list and then we print the max value. 07:12.340 --> 07:14.230 Let's run that. 07:14.260 --> 07:16.390 And you can see same behavior. 07:16.420 --> 07:18.010 We have 12. 07:18.340 --> 07:20.560 And note again that here we have a number list. 07:20.560 --> 07:21.820 And here as well. 07:21.850 --> 07:25.690 But this number list is a local variable inside the function. 07:25.900 --> 07:27.700 So that's why we can have it here. 07:27.730 --> 07:28.780 It's not going to be the same. 07:28.780 --> 07:33.250 And we also have a max value variable here and max value variable there okay. 07:33.250 --> 07:37.120 But that one as you see is created inside the function. 07:37.120 --> 07:40.030 So it's also local to this function okay. 07:40.060 --> 07:45.400 So the max value variable is not the same as that one because different scopes. 07:45.430 --> 07:46.000 Great. 07:46.000 --> 07:48.010 And that's the end of this activity.