1 00:00:00,520 --> 00:00:06,430 In this video, you will learn one of the most important elements of the Python programming language, 2 00:00:06,430 --> 00:00:08,350 and that is the full loop. 3 00:00:09,010 --> 00:00:12,670 So why do we need a full loop in this program? 4 00:00:12,760 --> 00:00:20,050 Well, when we execute the program and we add, for example, A to do clean and then we add another 5 00:00:20,050 --> 00:00:21,310 one at. 6 00:00:23,010 --> 00:00:23,820 Through. 7 00:00:24,340 --> 00:00:28,770 And then every press show, what we get is. 8 00:00:31,760 --> 00:00:33,110 A list. 9 00:00:33,410 --> 00:00:38,390 So this is a list object and it's not very user friendly. 10 00:00:38,810 --> 00:00:41,250 The user doesn't want to see brackets. 11 00:00:41,270 --> 00:00:43,460 They want to see just text. 12 00:00:43,460 --> 00:00:49,610 And they also don't want to see these quotes around the two two items. 13 00:00:50,120 --> 00:00:56,390 So how can we output H to do in one line? 14 00:00:56,390 --> 00:01:02,810 So 1 to 2 item per line without brackets, without commas, without quotes? 15 00:01:03,590 --> 00:01:13,130 Well, to do that we need to print out each of the two dos using a print function. 16 00:01:14,320 --> 00:01:22,990 So basically what we want to do is we want to go to the show case and instead of printing out the list 17 00:01:22,990 --> 00:01:33,490 with delete that and we save four item in to dos print item. 18 00:01:34,690 --> 00:01:38,830 So notice the level of indentation here. 19 00:01:39,850 --> 00:01:48,280 So the while loop is at the very first level of indentation and then match is. 20 00:01:50,250 --> 00:01:52,440 One level beneath that. 21 00:01:53,040 --> 00:01:54,810 And then we have case. 22 00:01:57,560 --> 00:02:02,390 At another level, then we have the full loop. 23 00:02:03,930 --> 00:02:06,270 So the full loop is indented. 24 00:02:06,270 --> 00:02:11,430 Three times one here, two and three. 25 00:02:14,180 --> 00:02:17,540 And so print is part of that loop. 26 00:02:17,570 --> 00:02:25,850 The function of this print function will be executed as many times as there are items in the to do list. 27 00:02:28,180 --> 00:02:29,650 So let me run this. 28 00:02:30,640 --> 00:02:33,220 Again at. 29 00:02:35,830 --> 00:02:38,320 Clean at again. 30 00:02:42,390 --> 00:02:43,140 Through. 31 00:02:43,320 --> 00:02:44,790 And now I want to show. 32 00:02:45,090 --> 00:02:48,020 Show presenter And there we go. 33 00:02:48,030 --> 00:02:49,050 That's the output. 34 00:02:50,550 --> 00:02:52,050 Clean and through. 35 00:02:53,630 --> 00:02:55,500 So that's above the full loop. 36 00:02:55,520 --> 00:03:00,100 We'll cover the full loop later on in the bonus example of. 37 00:03:00,110 --> 00:03:06,320 But what I wanted to show also is how to make a small improvement of our program, because what happens 38 00:03:06,320 --> 00:03:12,920 is that if you press add so the program is asking us to type in ADD, show or exit. 39 00:03:12,920 --> 00:03:18,860 And if you press add and then maybe you make a space, a whitespace character and then you press enter 40 00:03:19,130 --> 00:03:21,440 the program will not recognize. 41 00:03:23,220 --> 00:03:29,090 That's because it is not ad it is ads plus whitespace. 42 00:03:29,100 --> 00:03:32,580 So for Python that is a different string. 43 00:03:32,610 --> 00:03:34,920 So add. 44 00:03:37,620 --> 00:03:39,510 And add. 45 00:03:40,970 --> 00:03:42,770 If you use this comparison. 46 00:03:42,770 --> 00:03:43,640 Operator. 47 00:03:45,620 --> 00:03:46,730 You get fools. 48 00:03:46,730 --> 00:03:49,550 So those are not the same strings. 49 00:03:49,640 --> 00:03:54,850 Well, if you say ad is equal to ad. 50 00:03:56,330 --> 00:03:57,780 Yes, that is true. 51 00:03:57,800 --> 00:03:59,370 So that is a comparison. 52 00:03:59,390 --> 00:04:02,620 Operator is not it is not an assignment operator. 53 00:04:02,630 --> 00:04:06,290 It compares two values to check if they are the same. 54 00:04:06,860 --> 00:04:11,720 So how can we make our program more intelligent in this point? 55 00:04:13,340 --> 00:04:16,310 Well, we can simply apply here. 56 00:04:17,899 --> 00:04:23,390 A stream method which removes that trailing space from the string. 57 00:04:24,590 --> 00:04:27,110 So for that we can use the strip method. 58 00:04:27,260 --> 00:04:29,420 The strip method works like this. 59 00:04:30,350 --> 00:04:38,990 Let's say the user action, which is a variable, will be equal to add with a space. 60 00:04:39,400 --> 00:04:45,650 Then if you do user action that strip. 61 00:04:47,150 --> 00:04:51,350 And you press enter, you get at without the space. 62 00:04:51,830 --> 00:04:57,530 But know that if you call user action again. 63 00:04:59,330 --> 00:05:02,500 You will again get at with the space. 64 00:05:02,510 --> 00:05:06,830 So what happens here is that the strip method simply. 65 00:05:07,770 --> 00:05:15,390 Returns a new string, but it does not change the string in the user action variable. 66 00:05:17,310 --> 00:05:25,920 So if you want to save the changes to user action, you have to say user action equal to user action 67 00:05:26,130 --> 00:05:27,360 that strip. 68 00:05:29,940 --> 00:05:30,360 Execute. 69 00:05:30,360 --> 00:05:35,490 That's now user action is going to be ad without the trailing space. 70 00:05:35,940 --> 00:05:41,620 So this was just the Python console to have the changes in your code. 71 00:05:41,640 --> 00:05:45,810 Of course, you need to input that expression. 72 00:05:45,810 --> 00:05:47,100 So more in here. 73 00:05:48,360 --> 00:05:52,890 So I think we should put it in here. 74 00:05:52,950 --> 00:05:55,630 User action is equal to user action strip. 75 00:05:55,650 --> 00:06:04,020 So we get adds, show or exits, and if AD has a trailing space, we strip it. 76 00:06:04,050 --> 00:06:08,790 If show has a trailing space, which strip it out and so on for exit as well. 77 00:06:09,150 --> 00:06:18,600 So at this point we get a clean command without spaces and then we match that to add show or exit. 78 00:06:20,530 --> 00:06:27,380 So that was a nice addition to our program, and that's the for loop, which we will cover again later. 79 00:06:27,400 --> 00:06:28,690 So that's about now. 80 00:06:28,840 --> 00:06:29,740 See you later.