WEBVTT 00:00.080 --> 00:06.230 This is the solution for the activity number one, where you have to concatenate two strings and also 00:06.230 --> 00:07.790 put them uppercase. 00:07.790 --> 00:11.630 So first of all, if you manage to do the activity on your own, congratulations. 00:11.630 --> 00:14.540 And if you didn't manage to finish it well, it's okay. 00:14.570 --> 00:15.620 Don't worry too much. 00:15.800 --> 00:20.690 You can watch the solution and then you can go back to watch the concepts again and try it again, and 00:20.690 --> 00:22.400 maybe try again in a few days. 00:22.400 --> 00:26.660 And just practice until this activity becomes easy enough for you. 00:26.690 --> 00:27.140 All right. 00:27.140 --> 00:32.030 So I will remove all of that and let's create a function. 00:32.030 --> 00:35.450 So def how do we name our function. 00:35.450 --> 00:39.470 Well we want to concatenate strings and actually uppercase strings. 00:39.470 --> 00:48.710 So concatenate concatenate uppercase strings and I open the parentheses. 00:48.710 --> 00:52.850 You can see this name starts to be a bit long but it's still not that long okay. 00:52.880 --> 00:56.360 So as best practice is better to have short names. 00:56.360 --> 01:01.330 But even more important than that, it's better to have names that are meaningful. 01:01.360 --> 01:01.810 Okay. 01:01.810 --> 01:04.030 So here it's pretty explicit. 01:04.060 --> 01:06.760 So in the parentheses I'm going to add parameters. 01:06.760 --> 01:08.380 How many strings do I have. 01:08.380 --> 01:10.270 Well here I'm going to use two strings. 01:10.270 --> 01:16.780 I'm just going to name them str underscore a and str underscore b. 01:16.810 --> 01:17.170 Okay. 01:17.200 --> 01:20.350 Since we are only going to use that inside this function okay. 01:20.380 --> 01:23.590 And this is a local variable I can just use this name. 01:23.590 --> 01:24.820 It's not going to be a problem. 01:24.820 --> 01:31.210 So I close the parentheses I put a colon I go back to a new line with an indentation of four spaces 01:31.210 --> 01:31.570 here. 01:31.570 --> 01:34.300 And then let's do result. 01:34.330 --> 01:35.860 What will be the result. 01:35.860 --> 01:41.620 So we want to do str a plus str b. 01:41.680 --> 01:45.040 This will concatenate the two strings. 01:45.070 --> 01:48.910 But I also need to add a space in between okay. 01:48.940 --> 01:50.860 So I'm going to add a space. 01:50.860 --> 01:53.740 So we'll simply a quote like this with a space. 01:53.740 --> 02:01.080 And then plus okay so I can do plus between two strings, but also between three strings. 02:01.080 --> 02:03.420 I can add as many strings as I want. 02:03.450 --> 02:05.610 So here I'm adding three strings. 02:05.610 --> 02:12.180 This one that we get in a parameter, and then an empty character, and then the second string that 02:12.180 --> 02:14.880 will concatenate the two strings with a space. 02:14.880 --> 02:17.610 But we still need to put them uppercase. 02:17.610 --> 02:19.950 So I will do the first. 02:20.040 --> 02:24.900 So string a dot upper like this and open close parenthesis. 02:24.930 --> 02:29.220 And the same thing for the strb upper. 02:30.120 --> 02:37.020 This way we are going to first put the string a in uppercase, add a space and then the string B in 02:37.050 --> 02:37.860 uppercase. 02:37.860 --> 02:40.620 Let's save this file as. 02:40.620 --> 02:48.030 So save or save as and let's name it activity one dot p y. 02:48.900 --> 02:49.140 Okay. 02:49.170 --> 02:52.740 So I'm going to follow the same template for all activities. 02:52.740 --> 02:59.210 And then you can also download the code for each activity if you want to Click on okay. 02:59.210 --> 03:02.150 So it is saved. 03:02.150 --> 03:05.840 And then well if I run it the thing is you can see nothing happens. 03:05.840 --> 03:06.290 Why? 03:06.320 --> 03:11.150 Because we have defined a function but we don't use this function. 03:11.150 --> 03:13.700 And actually we don't even use this function. 03:13.700 --> 03:16.730 But we don't even return anything from the function. 03:16.730 --> 03:18.830 So I can do return result. 03:18.860 --> 03:19.400 Okay. 03:19.430 --> 03:26.000 Because if I just create the function like this, what is it going to compute the concatenation and 03:26.000 --> 03:27.530 put it inside the result variable. 03:27.530 --> 03:31.250 But if we don't return it well we're going to lose this result. 03:31.280 --> 03:34.790 But still it's not going to do anything because we don't call it. 03:34.790 --> 03:37.790 So I'm going to go back to a new line. 03:37.790 --> 03:41.960 And you can see it's important to go back to a new line with zero indentation here. 03:41.960 --> 03:44.780 If I do this we are still in the function okay. 03:44.810 --> 03:50.000 So I go here and I will do print concatenate concatenate. 03:50.000 --> 03:58.610 So here I'm going to use also the autocompletion I'm going to use Ctrl space and then tab or enter. 03:58.610 --> 04:01.070 So concatenate uppercase string. 04:01.070 --> 04:03.290 I'm going to say the first string is hello. 04:04.100 --> 04:04.760 Like this. 04:04.790 --> 04:07.970 And then a comma and then world. 04:08.030 --> 04:13.280 And then I close the parentheses and I need to close the parenthesis twice okay. 04:13.760 --> 04:17.990 One for this function and also one for the print function. 04:18.020 --> 04:20.210 Let's let's run it. 04:20.270 --> 04:22.580 And you can see we have the correct result. 04:22.610 --> 04:26.150 Hello world with a space and all uppercase. 04:26.180 --> 04:31.220 Now let's say for example if you have only one parameter. 04:31.220 --> 04:33.830 So let's say you don't give the correct amount of parameters. 04:33.830 --> 04:36.800 So here you give two few parameters. 04:36.800 --> 04:38.060 Let's see what happens. 04:38.540 --> 04:44.900 You have an error of course that says missing one required argument okay. 04:44.930 --> 04:50.510 So you need to provide exactly the same amount of parameters that you have in the function. 04:50.510 --> 04:53.240 So if you have two here it's going to be two here. 04:53.240 --> 04:55.630 If you have three you need to provide three Etc.. 04:55.630 --> 05:00.760 And look, what we can also do is because this is going to return a string, we need to pass a string 05:00.760 --> 05:01.570 as a parameter. 05:01.570 --> 05:06.010 So I can also call concatenate uppercase string here. 05:06.010 --> 05:07.690 So let's do concatenate. 05:08.110 --> 05:11.860 I'm going to use Ctrl and space again. 05:11.860 --> 05:16.480 And let's put world like that okay. 05:16.480 --> 05:17.800 And close the parenthesis. 05:17.800 --> 05:26.170 So basically what we do is we first concatenate some strings and actually not just world but hello and 05:26.170 --> 05:26.410 world. 05:26.410 --> 05:27.760 We need to pass two parameters. 05:27.760 --> 05:32.860 So we are going to call that first it's going to give us Hello world all uppercase. 05:32.860 --> 05:37.180 And then we're going to use the result as an input parameter for this function. 05:37.180 --> 05:40.090 So the same function again with hello. 05:40.090 --> 05:41.770 And then the result of that. 05:41.770 --> 05:44.860 And finally we print the whole thing okay. 05:44.860 --> 05:48.100 You can see you can really go far when combining functions. 05:48.100 --> 05:51.730 And make sure you can see that you close three parentheses okay. 05:51.760 --> 05:53.230 Let's see what happens. 05:53.890 --> 06:00.000 And now we have hello, Hello world because this one is going to give us Hello world. 06:00.030 --> 06:01.560 And then we add another hello. 06:01.560 --> 06:03.240 So hello, hello world. 06:03.240 --> 06:06.060 And just to finish here with optimization. 06:06.060 --> 06:08.790 Well again you can see we create a variable. 06:08.790 --> 06:10.410 We just return this variable. 06:10.410 --> 06:13.860 And this what anyway is created inside this function. 06:13.860 --> 06:18.420 We are not going to use it outside because it's only available in this scope. 06:18.420 --> 06:25.110 So if you just create a variable that you return immediately after that, you probably don't need the 06:25.110 --> 06:26.220 variable anyway. 06:26.220 --> 06:33.000 So instead of doing this, I'm just going to return the result and of course remove that line. 06:33.510 --> 06:36.030 So now we return directly the result. 06:36.060 --> 06:37.680 It's going to give us the same thing. 06:37.680 --> 06:38.130 Great. 06:38.130 --> 06:40.650 And that's the end of this first activity. 06:40.650 --> 06:44.310 So if it was too hard once again come back to the previous lessons. 06:44.310 --> 06:48.120 Try to do the activity again today, maybe another day okay. 06:48.150 --> 06:49.860 Give it some time, some practice. 06:49.860 --> 06:53.970 And at some point you will see you will manage to do it without any effort.