WEBVTT 0 00:00.140 --> 00:05.390 All right, guys, let's get back to learning about a few more things that we can do with strings. 1 00:05.660 --> 00:11.960 You saw in the last lesson that if we wanted to print things on individual lines, then we actually 2 00:11.960 --> 00:14.780 had to write them a few times, right? 3 00:14.780 --> 00:21.950 We had to write print on three lines if we wanted it to be printed one, two, three, 4 00:21.950 --> 00:23.000 like so. 5 00:23.120 --> 00:30.320 Now in this lesson, I want to show you a method where we can do the same thing, but by using a single 6 00:30.320 --> 00:33.830 print() method, so saving ourselves a few characters. 7 00:33.860 --> 00:41.750 So the way that we would create a new line is by writing a backslash and the n character (\n). 8 00:41.840 --> 00:50.120 And now if I go ahead and write "Hello world!" again afterwards, and I hit Run, and you can see that 9 00:50.120 --> 00:58.270 once that line of code has been executed, I've got "Hello world!" printed on two separate lines, separated 10 00:58.270 --> 01:04.480 by this \n character, which gets replaced by a new line. 11 01:05.470 --> 01:09.070 So go ahead and give that a go and see if you can create another one. 12 01:09.100 --> 01:12.910 Remember though, it's a backslash (\) and not a forward slash (/). 13 01:12.910 --> 01:15.370 But the syntax highlighting should help you. 14 01:17.770 --> 01:18.400 All right. 15 01:18.400 --> 01:26.280 We can simply just add another \n and remember that unless you want a space to appear right 16 01:26.280 --> 01:33.300 before where your "Hello world!" appears, you actually don't want any gaps between each of these lines. 17 01:35.970 --> 01:36.780 There we go. 18 01:36.780 --> 01:43.740 We've got the same result as before, but now using only a single print statement and creating some 19 01:43.740 --> 01:45.920 new lines with the \n. 20 01:46.370 --> 01:52.850 Now, one of the other things that we can do with strings is we can concatenate them. 21 01:53.030 --> 02:01.490 What this means is we combine different strings so that they will be added to the end of another string. 22 02:01.730 --> 02:03.080 Here's an example, 23 02:03.080 --> 02:11.260 let's say that we had the word Hello, and I wanted to add my name to the end of this word to make it 24 02:11.260 --> 02:12.700 a single string. 25 02:12.700 --> 02:21.400 Well, I can combine two strings by simply using a plus sign so I can write "Hello" + "Angela". 26 02:21.610 --> 02:23.350 Now here's a question, 27 02:23.350 --> 02:25.810 when this runs, what do you think it will look like? 28 02:25.810 --> 02:30.580 Do you think it'll write, Hello Angela or HelloAngela, 29 02:30.580 --> 02:31.900 all in one word? 30 02:32.350 --> 02:33.820 Let's see what happens. 31 02:34.480 --> 02:41.680 You can see that these two strings have now been combined into one, and there's no space in between 32 02:41.680 --> 02:46.210 because we don't have a space character anywhere in here. 33 02:46.420 --> 02:50.050 Pause the video and see if you can add a space in between. 34 02:52.690 --> 02:53.230 All right. 35 02:53.230 --> 02:55.330 So there's two ways that you can do this. 36 02:55.330 --> 02:59.460 Well maybe three actually, you could add a space to the end of Hello, 37 02:59.460 --> 03:06.480 you could add a space to the beginning of Angela, or you can actually continue using string concatenation 38 03:06.480 --> 03:11.490 by simply adding another string in between these two, 39 03:11.490 --> 03:14.340 and this one is just a space. 40 03:14.340 --> 03:21.750 So now when I run my code you can see the space gets inserted, and this long thing gets combined into 41 03:21.750 --> 03:25.700 a single string that looks like this 42 03:26.090 --> 03:35.840 once this bit of the code gets executed. If we think of strings as a string of connected characters, 43 03:35.870 --> 03:44.240 then string concatenation is simply taking those separate strings of characters and merging them into 44 03:44.240 --> 03:44.930 one. 45 03:45.920 --> 03:53.680 Now, this is a good point to mention that in Python programming spaces are really, really important. 46 03:53.860 --> 04:02.080 And what I mean by this is not so much the spaces that are inside strings like this one, but the spaces 47 04:02.080 --> 04:04.360 that you add in your code. 48 04:04.390 --> 04:12.550 So here you can see that the print statement starts at the very beginning of this Line 2, 49 04:12.580 --> 04:18.340 but what happens if I add a space before the print statement? 50 04:18.370 --> 04:22.660 Now you can see I've got the editor screaming at me already. 51 04:22.660 --> 04:29.350 I've got errors, I've got squiggly lines, and if I run this code as it is, I'll get something that's 52 04:29.350 --> 04:31.600 called an IndentationError. 53 04:31.630 --> 04:36.160 Now this is different to the previous error we had which was a SyntaxError. 54 04:36.190 --> 04:44.070 Now what this error tells you is that there is an unexpected indent around this part of your code. 55 04:44.070 --> 04:46.380 That's what the error message is telling me. 56 04:46.410 --> 04:54.840 So we can then go and investigate and see our squiggly lines and we can hopefully realize that, "Oops, 57 04:54.840 --> 05:01.440 we've added an extra space which we can easily get rid of," and it will calm everything down and get 58 05:01.440 --> 05:02.790 rid of that error. 59 05:02.840 --> 05:10.460 So remember, previously we were missing a closing quotation mark and we got a SyntaxError, 60 05:10.460 --> 05:20.150 and in this case, we have an indentationError by either adding in an aberrant space or accidentally inserting 61 05:20.150 --> 05:24.230 even a whole tab which is created using the tab key. 62 05:24.230 --> 05:28.160 And all of these things will give you indentation errors. 63 05:28.160 --> 05:34.640 So it's really important that you be careful when you're adding spaces in your Python code. 64 05:35.000 --> 05:40.790 It doesn't matter so much when we have spaces in between the quotation marks, because that's a part 65 05:40.790 --> 05:45.200 of the string, but anywhere that is a part of the code. 66 05:45.200 --> 05:51.080 So in this case, anything that's not green and you go ahead and add some spaces, you might end up 67 05:51.080 --> 05:53.230 with an IndentationError. 68 05:53.260 --> 05:59.530 Now you might also, when you add spaces in your code, not have an IndentationError because the code 69 05:59.530 --> 06:00.640 can function, 70 06:00.640 --> 06:04.450 for example, if I add a space between print and the parentheses, 71 06:04.450 --> 06:08.710 but in this case nothing really changes in terms of our output, 72 06:08.710 --> 06:14.740 but we do get a warning because this is not really ideally how we should format our code. 73 06:14.740 --> 06:22.020 So our warning tells us that according to PEP 8 and best practices, there shouldn't be whitespace before 74 06:22.020 --> 06:24.000 an open parenthesis. 75 06:24.000 --> 06:28.800 So we can also use that hint to get rid of any of these issues. 76 06:28.800 --> 06:33.210 So the message here is be careful when you're adding spaces. 77 06:33.210 --> 06:35.490 Make sure you know what it's doing, 78 06:35.490 --> 06:38.640 and when you see the error, IndentationError, 79 06:38.640 --> 06:47.330 remember what you learned in this lesson to be able to fix it. Now, as helpful as these warnings and 80 06:47.330 --> 06:54.770 errors are, you'll notice that I'm putting a lot of emphasis on looking at the errors that come out 81 06:54.770 --> 06:56.900 after we hit Run, 82 06:57.020 --> 07:01.430 and that's because this comes from the Python compiler itself. 83 07:01.430 --> 07:06.170 This will be the same whenever you write Python code. 84 07:06.200 --> 07:13.040 However, these squiggly lines and these errors that you get when you hover over them are specific to 85 07:13.040 --> 07:16.250 the editor that we're using here, which is PyCharm. 86 07:16.280 --> 07:22.190 Now, if you happen to be using a different type of editor, they might not give you the same kind of 87 07:22.190 --> 07:26.150 warnings, and they might not give you the same kind of errors. 88 07:26.150 --> 07:29.390 And the messages will also be wildly different. 89 07:29.390 --> 07:36.460 So it's always really important to learn the errors that you get back after you run your code, 90 07:36.460 --> 07:42.400 and to remember these words SyntaxError or IndentationError, 91 07:42.400 --> 07:49.870 and this is something that will help you no matter what tools you use, making you a more flexible developer. 92 07:49.870 --> 07:56.350 And we're going to see this in practice right now because I've got a debugging exercise coming up for 93 07:56.350 --> 08:04.140 you right after this lesson, and we're going to be doing it inside a different editor without the assistance 94 08:04.140 --> 08:06.900 of all of these helpful squiggly lines. 95 08:06.900 --> 08:15.780 So can you rely on your skills, your ability to debug when you run your code and see error messages, 96 08:15.780 --> 08:23.300 and go through each of the lines of the debugging exercise one by one, and fix each problem from top 97 08:23.300 --> 08:24.080 to bottom. 98 08:24.830 --> 08:33.140 This word debugging actually comes from a story where back in the 80s, a moth actually flew into one 99 08:33.140 --> 08:37.250 of the early computers and it got electrocuted, 100 08:37.250 --> 08:43.880 unfortunately for the moth, and for the programmer, it meant that his code wasn't performing as he would 101 08:43.880 --> 08:51.150 expect it to, so he actually had to go into the computer, pick out the moth and fix the wires so that 102 08:51.150 --> 08:52.170 it would work again. 103 08:52.560 --> 08:58.500 Now, we don't have any moths flying around in our code, thankfully, but what we do have to do is 104 08:58.500 --> 09:05.400 we have to pick out the errors so that our code will run in the way that we expect it to without any 105 09:05.400 --> 09:05.970 errors. 106 09:05.970 --> 09:11.430 So head over to the next lesson and try out your first debugging exercise.