1 00:00:03,180 --> 00:00:06,330 Next topic to be revised is code blocks. 2 00:00:06,330 --> 00:00:12,420 By code blocks I mean things like while loops for loops much case if live else. 3 00:00:13,680 --> 00:00:18,270 So these are multiple lines of code which have to stand together. 4 00:00:18,270 --> 00:00:22,350 For example, these two lines here make up a wild loop. 5 00:00:22,350 --> 00:00:28,320 So if you start with that line, you have to write the next lines indented under that line. 6 00:00:29,040 --> 00:00:31,770 So that's like a unit, a code block. 7 00:00:31,770 --> 00:00:39,810 Now, this wild loop here is an infinite loop in the sense that this will run forever because this condition 8 00:00:39,810 --> 00:00:41,130 here is always true. 9 00:00:41,130 --> 00:00:45,330 So that means this line will be executed over and over again. 10 00:00:45,330 --> 00:00:47,700 It will ask the user to enter inputs. 11 00:00:47,700 --> 00:00:57,990 Once the the user will enter that input, then it asks the user again to enter an input twice, thrice, 12 00:00:57,990 --> 00:00:58,740 etc.. 13 00:01:01,590 --> 00:01:03,120 While this year. 14 00:01:04,690 --> 00:01:07,660 Will run until this. 15 00:01:08,930 --> 00:01:10,310 Condition is satisfied. 16 00:01:10,310 --> 00:01:12,890 So this is some sort of finite loop. 17 00:01:14,210 --> 00:01:16,400 So it will ask the user to enter a password. 18 00:01:16,400 --> 00:01:20,810 But if the user happens to enter, pass one in the command line. 19 00:01:23,860 --> 00:01:24,310 Van. 20 00:01:24,310 --> 00:01:31,540 This condition will not be satisfied anymore because this condition says that, Oh, run this until 21 00:01:31,540 --> 00:01:34,570 the password is different from past one. 22 00:01:34,570 --> 00:01:39,700 So if the password is the same as past one, then the loop will not run anymore. 23 00:01:40,060 --> 00:01:50,230 And after the loop runs its last iteration, then the code after the wild loop is executed. 24 00:01:50,230 --> 00:01:54,490 So in this case, password is correct will be executed. 25 00:01:54,490 --> 00:01:56,200 For example, this is what happens. 26 00:01:56,200 --> 00:01:57,790 The user enters pass. 27 00:01:59,060 --> 00:02:03,700 Pass is not the same as pass one, so the loop will run again. 28 00:02:03,710 --> 00:02:04,660 Pass two. 29 00:02:04,670 --> 00:02:05,630 It's not the same. 30 00:02:05,630 --> 00:02:06,800 The loop run again. 31 00:02:06,810 --> 00:02:07,430 Pass one. 32 00:02:07,430 --> 00:02:09,740 Yes, pass one is the same as pass one. 33 00:02:09,740 --> 00:02:12,470 So in that case the loop will not run again. 34 00:02:12,470 --> 00:02:14,900 So password is correct will be executed. 35 00:02:14,900 --> 00:02:18,170 This line here for loops. 36 00:02:18,170 --> 00:02:25,100 For loops are also loops, but they are designed to run. 37 00:02:25,790 --> 00:02:30,200 As many times as there are items in a sequence such as the list. 38 00:02:30,200 --> 00:02:32,600 So we have this usernames list here. 39 00:02:32,720 --> 00:02:35,960 And so this loop will iterate three times. 40 00:02:35,960 --> 00:02:38,240 It will go through each of these items. 41 00:02:40,910 --> 00:02:45,140 And then capitalize that item and print them out in the terminal. 42 00:02:45,410 --> 00:02:46,400 As you can see here. 43 00:02:49,580 --> 00:02:50,810 Much case. 44 00:02:54,370 --> 00:02:57,670 Match case is a controlled flow code block. 45 00:02:59,200 --> 00:03:01,010 Let's see how we would use it here. 46 00:03:01,030 --> 00:03:06,520 So this program asks the user to enter a user name, so the user enters a username sim. 47 00:03:08,950 --> 00:03:14,050 And so the program then tries to match the user's value. 48 00:03:14,050 --> 00:03:22,690 So this variable username username, it tries to match the value of that variable against several cases. 49 00:03:24,960 --> 00:03:32,760 In this case it will execute print welcome user because the user entered sim in the. 50 00:03:33,630 --> 00:03:34,710 Command line. 51 00:03:36,920 --> 00:03:46,370 So match case can be used when you are simply trying to find out if a value is the same as another value. 52 00:03:46,490 --> 00:03:57,350 But for more complex comparisons, for example, in here we have this password pass and then this conditional 53 00:03:57,350 --> 00:03:57,790 block. 54 00:03:57,800 --> 00:03:58,700 If LS. 55 00:03:58,700 --> 00:04:04,310 So this now is trying to apply a more complex condition. 56 00:04:06,390 --> 00:04:13,230 If the length of the passwords is greater than three, it will do this else. 57 00:04:13,530 --> 00:04:17,790 If it's not greater than three, it will say password is weak. 58 00:04:18,510 --> 00:04:24,180 So and if else, conditional block is more appropriate for this scenario. 59 00:04:30,620 --> 00:04:35,600 And a conditional block can also include an l if condition. 60 00:04:36,290 --> 00:04:43,010 So when you want to count for more than two cases, for example, if the length of the password is greater 61 00:04:43,010 --> 00:04:49,550 than three, print that if the length of the password is equal to four prints, password is medium. 62 00:04:49,880 --> 00:04:51,080 Otherwise. 63 00:04:52,910 --> 00:04:54,230 Password is weak. 64 00:04:55,550 --> 00:04:58,670 So this line here will only be executed when. 65 00:05:00,740 --> 00:05:02,910 This condition is not evaluated. 66 00:05:02,960 --> 00:05:03,350 True. 67 00:05:03,350 --> 00:05:06,290 And this condition also is not evaluated through. 68 00:05:08,020 --> 00:05:10,480 One more topic for this video. 69 00:05:10,570 --> 00:05:11,680 F Strings. 70 00:05:13,410 --> 00:05:22,020 Let's consider that we have some value stored in variable, or maybe some functions are producing these 71 00:05:22,020 --> 00:05:23,160 values, right? 72 00:05:24,450 --> 00:05:30,930 If you want to construct a string where you want to enter some dynamic values, for example, some strings 73 00:05:30,930 --> 00:05:33,990 which are stored in some variables or some functions. 74 00:05:36,930 --> 00:05:39,960 Then you'd use this syntax. 75 00:05:39,960 --> 00:05:47,790 So you start the string with an F in front, and then inside the string you either enter literal text. 76 00:05:49,300 --> 00:05:54,790 All you enter variables, but variables should be entered inside curly brackets. 77 00:05:55,420 --> 00:05:59,850 You can also add some simple codes in these curly brackets. 78 00:05:59,860 --> 00:06:05,770 For example, here I have the variable and I've applied the capitalized methods and this expression 79 00:06:05,770 --> 00:06:06,910 will return. 80 00:06:09,270 --> 00:06:09,900 That. 81 00:06:10,590 --> 00:06:13,290 String, but with the end capitalized. 82 00:06:13,650 --> 00:06:18,150 Of course, you can also keep it like that if you don't want any to be cannibalized. 83 00:06:21,650 --> 00:06:27,380 And of course, you can enter more than one place holder as we have here, too. 84 00:06:27,500 --> 00:06:34,880 So message now will be containing that content with Nyah and inside the string. 85 00:06:35,780 --> 00:06:42,830 You'll see how f strings will become very useful in almost every application that we will build. 86 00:06:43,880 --> 00:06:44,960 And that's above this video. 87 00:06:44,960 --> 00:06:45,650 In the next one. 88 00:06:45,650 --> 00:06:47,780 Let's look at external files. 89 00:06:47,780 --> 00:06:48,380 See you there.