WEBVTT 00:01.120 --> 00:05.380 What happens once a for loop has finished executing. 00:05.410 --> 00:11.590 Usually you will want to summarize a block of output or move on to other work that your program must 00:11.590 --> 00:12.330 accomplish. 00:12.340 --> 00:21.310 Any lines of code after the for loop that are not intended are executed once without repetition. 00:21.310 --> 00:30.760 So let's write a thank you to a group of group of car makers as a whole and thanking them for putting 00:30.760 --> 00:33.130 on an excellent cars. 00:33.130 --> 00:39.010 So to display this group of message after all of the individual messages have been printed, we place 00:39.010 --> 00:39.490 them. 00:39.490 --> 00:44.020 Thank you message after the for loop without the indentation here. 00:44.020 --> 00:52.660 So now we will write print and thank you every car makers. 00:53.440 --> 00:59.020 These cars are special and great. 00:59.200 --> 01:07.910 And here now let's run this and you will see all this message is just executed once. 01:07.910 --> 01:17.660 So the first two cars to print are repeated once for each car makers in the list, as you saw earlier. 01:17.660 --> 01:23.870 However, because the last line is not intended, it's printed only once. 01:23.870 --> 01:29.360 If we add indentation to it, you will see, as you can see here, Thank you. 01:29.360 --> 01:35.030 Every car makers, thank you, every car makers, thank you, every car makers and so on. 01:35.420 --> 01:43.760 So we will delete this indentation and we will get this thank you message only once because it's not 01:43.760 --> 01:51.470 included in this loop because of the indentation we didn't put before the print here. 01:51.470 --> 01:57.740 So when you're processing data using a for loop, you will find that this is a good way to summarize 01:57.740 --> 02:01.450 an operation that was performed on an entire dataset. 02:01.450 --> 02:06.670 For example, you might want to use a for loop to initialize a game by running through the list of characters 02:06.670 --> 02:09.130 and displaying each character on the screen. 02:09.160 --> 02:15.640 You might then write some additional code after this loop that displays a play button. 02:15.640 --> 02:19.000 After all the characters have been drawn to the screen. 02:25.760 --> 02:33.360 Python uses indentation to determine how a line or group of lines is related to the rest of the program. 02:33.440 --> 02:41.480 In the previous in this examples the lines that printed messages to individual car makers were part 02:41.480 --> 02:44.510 of the for loop because they were indented. 02:44.640 --> 02:49.760 So python's use of indentation makes code very easy to read. 02:49.790 --> 02:58.430 Basically, it uses whitespace to force you to write neatly formatted code with a clear visual structure. 02:58.460 --> 03:03.400 In longer Python programs, you will notice block of code indented at a few different levels. 03:03.410 --> 03:10.190 These indentations levels help you gain a general sense of the overall program's organization. 03:10.190 --> 03:17.000 So as you begin to write code that relies on proper indentation, you will need to watch for a few common 03:17.030 --> 03:19.080 indentation errors. 03:19.100 --> 03:25.550 For example, people sometimes indent lines of code that don't need to be indented or forget the indented 03:25.650 --> 03:28.260 lines that need to be indented. 03:28.260 --> 03:34.620 So seeing examples of these errors now will help you avoid them in the future and correct them when 03:34.620 --> 03:37.170 they do appear in your own programs. 03:37.170 --> 03:46.740 So now let's examine some some of the more common indentation errors so you can also forget I here indent 03:46.890 --> 03:52.260 so always indent a line after the fourth statement in a loop. 03:52.260 --> 03:55.920 If you forget, Python will not remind you here. 04:00.760 --> 04:04.180 And as you can see here, expected and indented. 04:04.180 --> 04:04.930 Block. 04:06.180 --> 04:07.320 So here. 04:12.730 --> 04:22.390 If we write, for example car makers and just let the segmentation Eleanor also so the let's actually 04:22.390 --> 04:23.980 delete this and I will explain all of this. 04:24.070 --> 04:28.240 So the call to print should be indented. 04:28.360 --> 04:29.920 So but it's not here. 04:29.920 --> 04:36.940 So when Python expects an identity indented block and doesn't find one, it lets you know which line 04:36.940 --> 04:38.650 it had problem with. 04:38.980 --> 04:45.640 And if we run this code again and let's run it here, and as you can see, we have a indentation error 04:45.640 --> 04:47.590 at line three. 04:47.620 --> 04:58.060 So you can usually resolve these kinds of annotation errors by indenting the lines or lines immediately 04:58.060 --> 05:00.490 after the for statement. 05:00.520 --> 05:05.440 You can also forget things or forget to indent additional lines. 05:05.440 --> 05:13.400 So sometimes your loop will run without any errors but won't produce the expected result. 05:13.400 --> 05:20.690 So this can happen when you are trying to do several tasks in a loop and you forget to indent some of 05:20.690 --> 05:21.410 its lines. 05:21.410 --> 05:27.860 For example, this is what happens when we forget to indent the second line in the loop. 05:27.920 --> 05:29.120 And here. 05:32.130 --> 05:32.850 Do here. 05:32.880 --> 05:35.010 We will not get any error here. 05:35.630 --> 05:42.470 And now we'll if we run this and as you can see here, at List Object has no attribute title. 05:45.450 --> 05:48.360 As a result, the first print. 05:48.940 --> 05:53.440 And if if makers here this code will end as you can see. 05:53.440 --> 05:54.040 Let's. 05:55.520 --> 05:57.080 I'll make ups. 05:57.410 --> 05:58.010 I'll make. 05:59.490 --> 06:03.150 This code will run without a problem if you just edit it. 06:03.300 --> 06:06.450 Edit this and if we change this to car make. 06:07.710 --> 06:09.650 And we will get this as as well. 06:09.660 --> 06:11.550 So here. 06:12.530 --> 06:13.280 The. 06:15.860 --> 06:23.510 As the result here, the first printf call is not indented, is indented and. 06:25.360 --> 06:35.730 So the first that's why first print call is executed once for each name in the list because it's indented. 06:35.740 --> 06:43.870 But here the second print call is not indented, so it's executed only once after the loop has finished 06:43.870 --> 06:52.240 running because the final value associated with with Volkswagen here and Volkswagen is the only one 06:52.240 --> 06:54.880 who receives the looking who receives the. 06:54.880 --> 06:55.520 Thank you, Eric. 06:55.570 --> 06:56.080 Carmakers. 06:56.080 --> 06:57.570 These cars are special and correct. 06:57.580 --> 07:03.970 And Volkswagen, only one who gets the miles per gallon is high on Volkswagen. 07:04.920 --> 07:07.860 And here this is a logical error. 07:07.890 --> 07:13.470 This syntax is valid python code, but the code does not produce the desired result because a problem 07:13.470 --> 07:15.000 occurs in its logic. 07:15.030 --> 07:21.840 So if you expect to see certain action repeated once for each item in place and it's executed only once, 07:21.840 --> 07:26.070 determine whether you need to simply indent a line or group of lines. 07:26.070 --> 07:27.330 So here that's. 07:27.540 --> 07:34.710 Now we are getting this error here because in for loop, if you have a for loop here for now, let's 07:34.710 --> 07:36.600 print message will execute it once. 07:36.600 --> 07:42.090 But your program firstly execute your for loop again, again and again. 07:42.090 --> 07:47.040 And then after completing the for loop it will go to next lines here.