1 00:00:05,180 --> 00:00:09,300 The backslash character has got a special meaning in strings. 2 00:00:09,300 --> 00:00:14,259 It's used to escape the character that follows it, to give that character special meaning. 3 00:00:14,260 --> 00:00:21,000 Now some examples are backslash n, to start a new line, and backslash t to insert a tab. 4 00:00:21,000 --> 00:00:24,060 So let's go ahead and create a new Python file. 5 00:00:24,060 --> 00:00:36,200 I'm going to call this one escapechar.py 6 00:00:36,200 --> 00:00:42,860 Alright, so start by typing splitString is equal to, 7 00:00:42,860 --> 00:00:51,860 and in double quotes, This string has been, and we'll put a backslash n there, and type split over. 8 00:00:51,860 --> 00:00:57,860 Then backslash n several backslash n lines, 9 00:00:57,860 --> 00:01:05,060 and to confirm what this looks like, we're going to type print, and in parenthesis, splitString, like so. 10 00:01:05,060 --> 00:01:09,860 Now before I run this, remember to check what your IDE thinks you want to run. 11 00:01:09,860 --> 00:01:13,240 Now we haven't executed this code before, so we have to right click in the editor to run it from there, 12 00:01:13,240 --> 00:01:17,229 and you can see in the top right hand corner, 13 00:01:17,229 --> 00:01:19,920 it's going to run strings if we just click on this button here, 14 00:01:19,920 --> 00:01:21,960 which is not what we think should happen. 15 00:01:21,960 --> 00:01:27,280 So I'm just going to close that off. I'll just type in the answer there, close that off. 16 00:01:27,280 --> 00:01:31,000 So again, what we need to is right-click and select run. 17 00:01:31,000 --> 00:01:34,760 Alright, and now we can see those backslash characters and what they're doing. 18 00:01:34,760 --> 00:01:39,380 You can see how the string has been indeed spit over several lines in the output. 19 00:01:39,380 --> 00:01:42,999 So whenever the print function sees backslash n in a string, 20 00:01:43,000 --> 00:01:45,120 it causes it to start a new line. 21 00:01:45,120 --> 00:01:48,780 Many IDEs will color escape characters differently in the code, 22 00:01:48,780 --> 00:01:54,940 as IntelliJ IDEA is doing on my screen. You can see that on line 1, the various backslash ns there. 23 00:01:54,940 --> 00:01:58,740 Alright, so that was backslash n. We can also tab the output. 24 00:01:58,740 --> 00:02:05,800 So using backslash t causes Python to tab to the next stop before printing. So let's go ahead and try that. 25 00:02:05,800 --> 00:02:20,280 So I'm going to type tabbedString is equal to, and in double quotes I'm going to type 1\t2\t3\t4, you guessed it, \t5. 26 00:02:20,280 --> 00:02:28,320 Alright and then print that out to print and in parentheses, tabbedString this time, and we'll run this. 27 00:02:28,320 --> 00:02:33,280 We can see the numbers 1 to 5 are printed out, tabbed across the screen. 28 00:02:33,280 --> 00:02:40,060 Now different consoles have different tab stops. In IDEA, the tab stops are every four characters. 29 00:02:40,060 --> 00:02:43,100 But if you run this program from, say, a terminal or a command prompt, 30 00:02:43,100 --> 00:02:47,840 the tab stops will probably be set to eight characters, so keep that in mind. 31 00:02:47,840 --> 00:02:53,180 So the backslash can also be used to escape special characters, such as quotes and double quotes, 32 00:02:53,180 --> 00:02:57,160 and that can be useful if they you've got a string containing both of those characters. 33 00:02:57,160 --> 00:02:59,760 So to see what I mean, let's type some more code. 34 00:02:59,760 --> 00:03:04,220 So I'm going to type print parenthesis and single quote, 35 00:03:04,220 --> 00:03:14,840 and I'm going to type The pet shop owner said, and then double quote, No, no, and a space, we're gonna put a 36 00:03:14,840 --> 00:03:24,480 backslash single quote, bear with me here, e backslash single quote again, s then r. 37 00:03:24,480 --> 00:03:33,440 Hopefully you're recognizing the reference here, and three periods, he backslash single quote s resting, 38 00:03:33,440 --> 00:03:39,480 and closing double quote, a period and a single quote which is already there, and the right parenthesis. 39 00:03:39,480 --> 00:03:41,860 So that's one option, or what we can do, 40 00:03:41,860 --> 00:03:44,564 is we can come back and also try another version of that, 41 00:03:44,564 --> 00:03:51,180 and we can put, and I'll put a comment there, hash or. We can do it another way print, and put a double quote this time, 42 00:03:51,180 --> 00:03:58,260 The pet shop owner said, space backslash double quote 43 00:03:58,260 --> 00:04:06,200 No, no, space single quotes e, and we're putting the e in single quotes there, 44 00:04:06,200 --> 00:04:13,500 s for e's uh comma three periods, he's resting. 45 00:04:13,500 --> 00:04:16,760 Then we want to put a backslash double quote a period, 46 00:04:16,760 --> 00:04:21,760 then we've got the closing double quote from the start of the line, and the right parentheses. 47 00:04:21,760 --> 00:04:25,360 Let's just run this first. 48 00:04:25,360 --> 00:04:31,240 So you can see now that what the pet shop owner said is in double quotes, but his statement includes apostrophies, 49 00:04:31,240 --> 00:04:33,460 and that means that we have to escape one or the other. 50 00:04:33,460 --> 00:04:36,960 So on line 7, the string is delimited with single quotes, as you saw, 51 00:04:36,960 --> 00:04:40,080 and we have to escape any single quotes that appear in the string. 52 00:04:40,080 --> 00:04:44,760 However, on line 9 what we've done, is we've delimited using double quotes, 53 00:04:44,760 --> 00:04:48,740 and that means the double quotes inside the string must be escaped. 54 00:04:48,740 --> 00:04:53,080 Now another alternative is when you use triple quotes, which we'll do now, 55 00:04:53,080 --> 00:04:58,080 there's no need to escape any quotes inside the string. So I'm going to type print 56 00:04:58,080 --> 00:05:03,940 left parenthesis and three double quotes, and noting that IntelliJ added the last three for us automatically, 57 00:05:03,940 --> 00:05:10,200 and I can type The pet shop owner said, 58 00:05:10,200 --> 00:05:17,520 then a double quote. Notice we're not using the backslash now for escape characters, no, no, single quote, 59 00:05:17,520 --> 00:05:27,300 e single quote, s for e's uh semicolon three periods, he single quote he's resting. 60 00:05:27,300 --> 00:05:32,880 Then we've got our double quote to close off the quote, from the start of No, no, he's uh, ... he's resting 61 00:05:32,880 --> 00:05:38,020 and we want to put a period there, and we'll just put a space and the three double quotes on the right-hand side. 62 00:05:38,020 --> 00:05:40,740 Close off the print line with the right parenthesis. 63 00:05:40,740 --> 00:05:46,000 So basically, when we're using triple quotes there, there's no need to escape any quotes inside the string. 64 00:05:46,000 --> 00:05:51,300 Python knows that the string doesn't end, until it finds those matching triple quotes at the end. 65 00:05:51,300 --> 00:05:54,340 And just to confirm this we'll run it, 66 00:05:54,340 --> 00:05:57,080 and as you can see, we've got exactly the same output. 67 00:05:57,080 --> 00:05:59,960 So another reason we might want three consecutive quotes 68 00:05:59,960 --> 00:06:05,100 is because of a feature Python provides, to make strings spanning lines more readable. 69 00:06:05,100 --> 00:06:11,080 So the string that we split over several lines earlier, is not easy to read because of the embedded backslash ns. 70 00:06:11,080 --> 00:06:16,640 but Python allows the string to be split over several lines without doing that, by using triple quotes 71 00:06:16,640 --> 00:06:19,320 So to see what I mean, let's type some code in. 72 00:06:19,320 --> 00:06:28,920 We'll do this on line 13. So I'm going to type anotherSplitString is equal to, three double quotes, 73 00:06:28,920 --> 00:06:39,640 This string has been, I'm pressing enter there, split over, enter, several, enter, lines. 74 00:06:39,640 --> 00:06:47,000 Then on the next line, which is the line after, just to make it clear, and I'm gonna print another string, anotherSpitString. 75 00:06:47,000 --> 00:06:50,460 If we run that, 76 00:06:50,460 --> 00:06:53,780 and you can see This string has been split over several lines. 77 00:06:53,780 --> 00:06:56,120 So we're basically getting line breaks in the output. 78 00:06:56,120 --> 00:07:01,660 Now if you want to lay out a string with breaks, but don't want every one to start with a new line when printed, 79 00:07:01,660 --> 00:07:05,740 then what you can do is escape the end of a line with a backslash. 80 00:07:05,740 --> 00:07:07,580 So to see what I mean there, 81 00:07:07,580 --> 00:07:13,540 we can come to the end of the line. We'll come up here to line 13, has been been space, we'll put a backslash there. 82 00:07:13,540 --> 00:07:19,240 On the next line, do the same, space backslash several backslash after the space, 83 00:07:19,240 --> 00:07:22,240 and now if we run this, you'll see the difference in the output. 84 00:07:22,240 --> 00:07:25,140 The string has been split over several lines, is actually no longer true. 85 00:07:25,140 --> 00:07:30,520 It's now all on the same line because we've used the backslash to escape the end of the line. 86 00:07:30,520 --> 00:07:32,500 Alright so let's finish the video here. 87 00:07:32,500 --> 00:07:35,180 See you in the next video.