1 00:00:00,690 --> 00:00:06,150 Like in this lecture, I want to talk about the strings and in particular ways to print strings out 2 00:00:06,150 --> 00:00:09,480 into the show and format those printouts. 3 00:00:10,230 --> 00:00:15,120 Before we begin, I just want to show you an interesting module that I found recently, and that is 4 00:00:15,120 --> 00:00:21,080 the string module, which is available with C Python, but not with micro python. 5 00:00:21,300 --> 00:00:27,960 And what this does is to provide to a number of string constants that can be useful in some particular 6 00:00:27,960 --> 00:00:28,400 cases. 7 00:00:28,410 --> 00:00:34,030 For example, if you want to have the ability to quickly get a list of all ASCII located characters, 8 00:00:34,050 --> 00:00:37,200 and you can do so by calling this constant. 9 00:00:37,200 --> 00:00:45,560 Here to give you an example is that by importing the string module like this and then you can say the 10 00:00:45,570 --> 00:00:56,130 string don't ASCII on this call uppercase and that will give you all uppercase characters. 11 00:00:56,910 --> 00:00:57,950 Same thing with digits. 12 00:00:57,960 --> 00:00:59,130 I'm just going to copy this time. 13 00:01:00,090 --> 00:01:02,930 String digits will give you digits. 14 00:01:03,450 --> 00:01:07,330 So I thought it's a useful module for some applications. 15 00:01:07,330 --> 00:01:08,400 That interesting to show. 16 00:01:08,910 --> 00:01:12,200 But let's go into the main part of what this lecture is about. 17 00:01:12,210 --> 00:01:20,100 And that, again, as I said, it's printing now my sources for what I'm about to show you in case you 18 00:01:20,100 --> 00:01:25,550 want to go deeper and do a bit of study on your own from the Python three documentation. 19 00:01:25,560 --> 00:01:28,830 The first one is from the informal introduction to Python. 20 00:01:28,830 --> 00:01:33,090 And I'm looking at the strings component here, strings section. 21 00:01:33,420 --> 00:01:39,630 And I'm also looking at inputs and outputs, which is also part of the input output tutorial. 22 00:01:40,080 --> 00:01:45,330 And eventually I'm going to show you a few things out of the format specification, mini language, 23 00:01:45,780 --> 00:01:51,870 which is probably the most powerful way to format the strings in Python. 24 00:01:52,350 --> 00:02:00,780 And Python is on its own and extremely capable language for anything that has to do with string manipulation 25 00:02:00,780 --> 00:02:02,440 and string processing. 26 00:02:03,240 --> 00:02:06,480 So let's begin with a little example. 27 00:02:06,480 --> 00:02:09,300 Let's say that you have a bunch of variables. 28 00:02:09,510 --> 00:02:15,060 So one of those is A that contains the screen. 29 00:02:16,410 --> 00:02:21,180 Another one is B, which contains numerical integer one. 30 00:02:21,450 --> 00:02:30,210 And it's at C, which contains, of course, the world actually looking at the space there just like 31 00:02:30,210 --> 00:02:30,450 that. 32 00:02:31,170 --> 00:02:33,220 Now, let's say that you want to print it out. 33 00:02:33,540 --> 00:02:38,980 So the easiest way to print strings out is to use the print command. 34 00:02:39,000 --> 00:02:44,100 Now the print command allows you to do things such as add variables like that. 35 00:02:44,580 --> 00:02:46,640 You can add multiple variables as well. 36 00:02:46,650 --> 00:02:51,920 So you just can add a space here and then add variable C. 37 00:02:52,530 --> 00:02:59,220 And what this will do now is create one single print out where it's called the contents of the two variables, 38 00:02:59,220 --> 00:03:09,330 A and C plus a string that I typed in manually in between, and those are separated by commas. 39 00:03:10,410 --> 00:03:17,580 So that way you can write a program that can do various calculations to the results of those calculations 40 00:03:17,580 --> 00:03:18,840 in variables. 41 00:03:18,840 --> 00:03:25,950 And those drivers, of course, can be strings or numerical and then use a single print command when 42 00:03:25,950 --> 00:03:30,690 you add all those variables together via commerce. 43 00:03:30,990 --> 00:03:34,400 So that comma separated and then you have a single printout. 44 00:03:34,950 --> 00:03:42,210 You can also had no so not confined to printing out variables of the same data type. 45 00:03:42,660 --> 00:03:50,400 So I'm going to add another comma, this time in between double quotes and then print out B or the value 46 00:03:50,400 --> 00:03:54,850 stored in both B, which is a numerical one and it looks like this. 47 00:03:55,950 --> 00:04:04,470 So this is perhaps the easiest way to print out a string or a combination of strings that don't require 48 00:04:04,680 --> 00:04:06,450 much formatting. 49 00:04:06,990 --> 00:04:11,910 One more thing that I want to show you is that you can also add special characters. 50 00:04:11,910 --> 00:04:18,720 So, for example, let's say that you want to have a line break between hello and world, which you 51 00:04:18,720 --> 00:04:19,670 can do it. 52 00:04:19,680 --> 00:04:29,910 You can add a new line special character which is shaped by the backslash, and that will give you a 53 00:04:30,120 --> 00:04:38,420 line said right there, then break the rest of the string, print out into a separate line with others. 54 00:04:38,430 --> 00:04:45,060 For example, you can add a backslash T and that will give you a tab. 55 00:04:45,600 --> 00:04:50,640 You can see that the numerical one is pushed out towards the right. 56 00:04:51,900 --> 00:04:57,720 One more thing that I want to show you before we move on to the next item in my list to talk about in 57 00:04:57,720 --> 00:05:08,430 this lecture is that you can also use the backslash escape character to produce things such as a single 58 00:05:08,430 --> 00:05:08,970 quote. 59 00:05:09,750 --> 00:05:12,930 I could put it like that and. 60 00:05:14,620 --> 00:05:20,560 Then, of course, they care, of course, the ticket should be after the escape character like this 61 00:05:20,560 --> 00:05:24,970 and let's close it this way. 62 00:05:25,570 --> 00:05:35,290 So now our print out appears like this and there is no one at peering enclosed inside single quotes. 63 00:05:35,290 --> 00:05:38,190 But of course, you can use double quotes as well if you wish. 64 00:05:38,230 --> 00:05:46,620 So as they are after the escape character, which is the backslash narratives like this. 65 00:05:47,440 --> 00:05:57,040 So the print function on its own allows you to create strings that are composed of individual components, 66 00:05:57,040 --> 00:06:03,700 either values stored in variables or explicitly included in the print statement. 67 00:06:03,820 --> 00:06:06,350 And you've got all those components separated by commas. 68 00:06:07,150 --> 00:06:15,490 You can also use the escape character to create things such as a new line or a tab or single or double 69 00:06:15,640 --> 00:06:16,180 quotes. 70 00:06:16,930 --> 00:06:26,560 Now, if you want to add formatting, then in this course will be using the format specification in 71 00:06:26,560 --> 00:06:27,280 the language. 72 00:06:27,820 --> 00:06:35,980 I'm going to give you some examples if you want to format your string, not just to print it. 73 00:06:35,980 --> 00:06:38,380 And I recommend that you learn the format specification. 74 00:06:38,380 --> 00:06:40,650 Middle language is going to give you some examples. 75 00:06:40,660 --> 00:06:45,020 And as you'll see, it's very simple and we'll be using it throughout this course. 76 00:06:45,520 --> 00:06:50,050 So the formal specification language looks like this. 77 00:06:50,560 --> 00:06:52,090 You've got a string. 78 00:06:53,470 --> 00:07:00,820 Just a regular string, and in that string, you've got a curly bracket open and close which create 79 00:07:00,820 --> 00:07:06,850 placeholders and a few different kinds of placeholders, but the simplest one is this one is the anonymous 80 00:07:06,850 --> 00:07:07,690 placeholder. 81 00:07:08,450 --> 00:07:16,810 You have as many of those as you want, and then you need to use the format function on the string. 82 00:07:16,990 --> 00:07:23,610 You can see that string and you've got a dot notation to bring up its format function. 83 00:07:23,980 --> 00:07:31,870 And then inside the format function, you list the things that you want to use in order to replace the 84 00:07:31,870 --> 00:07:35,740 placeholders that you have placed in the string. 85 00:07:36,430 --> 00:07:41,170 So in this case, we've got this string to placeholders. 86 00:07:42,870 --> 00:07:47,930 Three other items that will be used to replace as placeholders in the end result looks like this. 87 00:07:48,870 --> 00:07:55,380 And apart from the anonymous placeholder, you also have the ability to enumerate them so you can give 88 00:07:55,380 --> 00:07:56,280 them a number. 89 00:07:57,610 --> 00:07:58,810 Or we can give them a name. 90 00:08:00,600 --> 00:08:04,120 We can give them format's as well, as you can see right here. 91 00:08:04,140 --> 00:08:09,510 We've got a placeholder which will be formatted as a digital renumber. 92 00:08:11,260 --> 00:08:18,670 Let me show you a few examples that I think to remember here is that the print function and the format, 93 00:08:18,670 --> 00:08:24,500 many language works exactly the same on Python as it does on micro python. 94 00:08:24,520 --> 00:08:27,690 So everything I'm going to show you works in both types of python. 95 00:08:28,780 --> 00:08:31,600 So I'm going to copy a little bit of text here. 96 00:08:31,750 --> 00:08:33,530 So it saves me the typing. 97 00:08:34,360 --> 00:08:36,790 So there's a little string. 98 00:08:38,100 --> 00:08:39,050 Can print it out. 99 00:08:41,130 --> 00:08:48,360 Using the print command and you get what you expected, Michael Python on the E.S.P thirty two Teletón 100 00:08:48,390 --> 00:08:52,040 hands and that by including a placeholder. 101 00:08:52,050 --> 00:08:59,790 So in this case I've got the placeholder with my open and close curly brackets and that becomes a variable. 102 00:09:00,510 --> 00:09:02,580 I want to create one more variable. 103 00:09:05,090 --> 00:09:06,260 Named a.. 104 00:09:08,250 --> 00:09:17,160 And then I'm going to do printing, so what I've got here is the string, which remember contains this 105 00:09:17,160 --> 00:09:24,270 with the placeholder, inserted a single placeholder, and then I'm calling the format function and 106 00:09:24,270 --> 00:09:27,600 I am passing another variable that is variable. 107 00:09:27,600 --> 00:09:33,960 Being inside the form and function means that it will be used or will get its value to replace the single 108 00:09:33,960 --> 00:09:34,750 placeholder. 109 00:09:35,610 --> 00:09:40,650 So once that is evaluated, we get this completed string. 110 00:09:41,460 --> 00:09:43,920 OK, so that is pretty cool. 111 00:09:44,460 --> 00:09:46,230 It means that if we change. 112 00:09:47,990 --> 00:09:59,330 Something in our expression like this, we've got an updated adjective, then the print command will 113 00:10:00,380 --> 00:10:03,740 re-evaluate the expression and give us a new string. 114 00:10:04,370 --> 00:10:13,070 Now, if you have a single location where you want to place some string that comes from a variable, 115 00:10:13,280 --> 00:10:14,890 the expression is not complex. 116 00:10:14,900 --> 00:10:20,540 So you don't need to worry about the anonymity of the placeholder. 117 00:10:20,990 --> 00:10:28,070 But if you have more, then it's a good practice and a good idea to start naming your placeholders. 118 00:10:28,610 --> 00:10:31,690 So I'm going to give you an example of how that can be done. 119 00:10:31,700 --> 00:10:36,860 So I'm going to recreate or reset the my string variable. 120 00:10:37,970 --> 00:10:42,650 But this time, instead of using an anonymous placeholder, we'll give it a name. 121 00:10:42,650 --> 00:10:49,200 So we put the name inside the curly brackets like this so we can have as many of those as you want. 122 00:10:49,220 --> 00:10:51,110 Each one will have its own name. 123 00:10:51,800 --> 00:10:57,260 The adjectives just going to reset it to a single word. 124 00:10:57,710 --> 00:10:58,430 Amazing. 125 00:10:59,590 --> 00:11:06,340 And now to have a look at the print statement, remember that the place for the now has a name, so 126 00:11:06,700 --> 00:11:16,870 inside format, I need to use the name of the placeholder in order to pass the variable that I want 127 00:11:16,870 --> 00:11:18,460 to use at its place. 128 00:11:19,360 --> 00:11:20,970 So enter. 129 00:11:21,010 --> 00:11:23,350 And the result is exactly the same. 130 00:11:23,980 --> 00:11:26,860 The only difference is that the placeholder now has a name. 131 00:11:29,000 --> 00:11:34,400 And once you get the hang of this, then the complexity can increase. 132 00:11:36,220 --> 00:11:46,270 So in this example, expanding on my string, I've got a target as well as a word that allows me to 133 00:11:46,480 --> 00:11:48,790 have two variables inside this string. 134 00:11:50,260 --> 00:11:56,610 So the adjective is still amazing, let's come up with an MCU you now here's a new variable MCU, which 135 00:11:56,610 --> 00:11:57,730 you say is considered too. 136 00:11:58,150 --> 00:12:08,740 And now the print statement, of course, needs to address the two placeholders, the two named placeholders, 137 00:12:08,770 --> 00:12:13,770 a word and the target a word, and putting the adjective which we've already found a bit earlier. 138 00:12:14,230 --> 00:12:18,930 And for the target, I'm going to pass MCU, which is defined right here. 139 00:12:20,660 --> 00:12:23,710 And there you go, I could python on the East Coast. 140 00:12:23,780 --> 00:12:24,980 It is amazing. 141 00:12:25,930 --> 00:12:32,380 And we're going to play with numbers, and that's where formatting will come in and show you a few examples 142 00:12:32,380 --> 00:12:32,650 there. 143 00:12:32,680 --> 00:12:37,870 So let's start with a let's make that a 13 point number. 144 00:12:37,870 --> 00:12:46,180 One point to be is going to be one point five and see, it's going to be three point two and it's off 145 00:12:46,180 --> 00:12:47,370 to do a calculation. 146 00:12:47,830 --> 00:12:53,410 Let's make the equals eight times. 147 00:12:55,790 --> 00:12:58,970 Make the times see. 148 00:13:00,190 --> 00:13:05,640 All right, so if you say print the you will get this number. 149 00:13:05,930 --> 00:13:12,040 You see how many decimals it has at four point eight with a large number of zeroes. 150 00:13:12,340 --> 00:13:18,040 So I can create a string out of this calculation and out of these numbers. 151 00:13:18,410 --> 00:13:21,730 So I'm going to say a calculation 152 00:13:24,130 --> 00:13:28,990 is equal and now I'm going to use placeholders. 153 00:13:29,030 --> 00:13:31,090 So I'm going to go for number one. 154 00:13:33,470 --> 00:13:35,900 Times to. 155 00:13:38,920 --> 00:13:39,760 Equals. 156 00:13:42,470 --> 00:13:45,570 The result is one result. 157 00:13:46,790 --> 00:13:48,050 So we've got a string. 158 00:13:49,390 --> 00:13:54,430 The string is composed or contains three placeholders with their individual names. 159 00:13:57,220 --> 00:14:04,480 You know, I can do a print, so let's print out a calculation. 160 00:14:06,340 --> 00:14:13,210 It just hit the tab key and then Anthony completed the rest of my expression here, the name of the 161 00:14:13,210 --> 00:14:23,440 variable adult format, a couple of letters out of the word format, and then the turkey and Thorney 162 00:14:23,440 --> 00:14:28,510 will give me a choice of functions that match at that point. 163 00:14:28,960 --> 00:14:36,310 So I'm going to format and open parentheses and only to put in the appropriate placeholder names, which 164 00:14:36,310 --> 00:14:37,960 I've got no one for, no one. 165 00:14:37,970 --> 00:14:48,490 I'm going to say that I want to pass the variable for detail and for number two possible before see. 166 00:14:50,290 --> 00:14:58,840 And for result, I'm going to actually do the calculation. 167 00:14:59,230 --> 00:15:08,680 I can either do the calculation here in line as this bad times see, or I can just say D since I have 168 00:15:08,680 --> 00:15:10,550 defined that calculation up here. 169 00:15:12,130 --> 00:15:12,610 All right. 170 00:15:14,540 --> 00:15:22,640 And close parentheses and then close the second set of parentheses and enter and now we get this very 171 00:15:22,640 --> 00:15:29,840 long string of text, but I would like to do next is to format these numbers. 172 00:15:29,870 --> 00:15:34,260 So the first two numbers don't look that, but the result looks pretty bad. 173 00:15:34,340 --> 00:15:37,940 I just want to go, say, up to two decimals maximum. 174 00:15:38,690 --> 00:15:48,340 So to do that, need to go back into the a calculation definition and use the format expressions. 175 00:15:48,680 --> 00:15:56,180 In this case, I want to use the zero point two expression of floating point number, which means that 176 00:15:56,690 --> 00:16:06,440 what is printed out of this placeholder is a floating point number with two decimal points after the 177 00:16:06,440 --> 00:16:06,740 dot. 178 00:16:07,810 --> 00:16:13,290 Someone do the same thing for zero four zero, so there's going to be zero point two as. 179 00:16:15,050 --> 00:16:22,840 And finally, for the results, definitely this one I wanted to be sure to point to yes. 180 00:16:24,170 --> 00:16:27,110 For the floating point number of the result. 181 00:16:28,910 --> 00:16:34,470 Now, let's reprint and you get a much better looking result here. 182 00:16:34,520 --> 00:16:40,500 One point fifty three times three point twenty equals four point eight zero. 183 00:16:41,960 --> 00:16:45,680 So this is an example of what you can do with the format function. 184 00:16:45,680 --> 00:16:50,840 As I said, I'll be using it a lot in the remainder of this course. 185 00:16:50,840 --> 00:16:57,440 And I encourage you to have a look at this documentation here for the format specification in any language, 186 00:16:57,440 --> 00:17:00,800 because there's a lot more to it than what I've shown you. 187 00:17:00,980 --> 00:17:04,850 What I've shown you is enough for the purposes of this course. 188 00:17:04,850 --> 00:17:11,060 But if you want to dig into it and learn more details and documentation, here is where you need to 189 00:17:11,060 --> 00:17:11,240 get.