WEBVTT 00:00.530 --> 00:02.090 Let's go back to strings. 00:02.090 --> 00:09.410 So we've used the strings throughout the course so far, but we haven't really went deep on them. 00:09.410 --> 00:14.450 So I think it's time that we really dive deeper into strings. 00:14.450 --> 00:20.630 So let's begin with the simplest thing, which is the single and double quote strings. 00:20.750 --> 00:25.910 So there are two types of strings in PHP the single and double quotes. 00:25.910 --> 00:27.740 Here you see the double quote strings. 00:27.740 --> 00:35.000 And what characterizes the double quote strings is that they can interpolate data. 00:35.000 --> 00:40.730 So interpolating essentially means that you can use a variable like name or any expression. 00:40.730 --> 00:44.420 And this would be outputted on the screen like in this example. 00:44.690 --> 00:51.200 So you can also add and use special characters like new line, tab etc.. 00:51.260 --> 00:56.870 Now with single quote strings everything inside is treated literally. 00:56.870 --> 01:08.510 So there are no special characters except maybe an escape character and except a single quote ending 01:08.510 --> 01:09.260 character. 01:09.290 --> 01:15.050 Everything else is treated as you would mean a literal string, as in this example. 01:15.080 --> 01:17.210 That would be the output. 01:18.710 --> 01:21.470 So I've already created the strings php file. 01:21.470 --> 01:23.210 You can just grab it from GitHub. 01:23.210 --> 01:26.630 Let's run it so I can do strings. 01:26.630 --> 01:29.690 And we see exactly what I've described. 01:29.690 --> 01:35.450 So with the first example single quotes nothing is actually interpolated. 01:35.450 --> 01:39.860 Everything is treated literally with the second double quote example. 01:39.860 --> 01:46.520 We can clearly see that in place of the name variable here John is outputted as that's the value of 01:46.520 --> 01:47.390 the variable. 01:47.420 --> 01:51.320 Now let's see the different kinds of strings. 01:51.320 --> 01:55.700 So even if you have used PHP before you might not have heard about them. 01:55.700 --> 01:58.190 First is a heredoc syntax. 01:58.280 --> 02:00.020 This is pretty strange. 02:00.110 --> 02:02.180 So we've added those symbols. 02:02.180 --> 02:06.080 You write your code, then end and semicolon. 02:06.080 --> 02:08.690 Now everything between those characters. 02:08.690 --> 02:16.490 The starting and ending lines is actually a multi-line string, so you are free to write multi-line 02:16.490 --> 02:19.280 strings, which wouldn't be really easy. 02:19.280 --> 02:26.240 With single or double quotes, you would have to use a concatenation character, and it would really 02:26.240 --> 02:33.620 be odd to put, uh, those kind of strings into multi-line strings with this heredoc syntax. 02:33.620 --> 02:34.670 This is easy. 02:34.700 --> 02:37.340 Now there are two variants of this. 02:37.340 --> 02:43.760 There is Heredoc and there is another one called now doc. 02:43.760 --> 02:51.680 Now the difference between them is, uh, this actually can have single quotes here. 02:51.860 --> 02:54.860 The difference is pretty simple. 02:54.860 --> 03:02.450 With the here doc you've got interpolation and with now doc you don't. 03:02.480 --> 03:04.400 So those are like single quotes. 03:04.400 --> 03:07.430 And this syntax is like double quotes. 03:07.430 --> 03:08.810 So let's run it. 03:08.810 --> 03:13.370 This is string speech P. 03:13.850 --> 03:17.270 Um yeah I obviously forgot to echo those. 03:17.270 --> 03:24.780 So let me echo here dog and the now dog and let's see this. 03:24.780 --> 03:28.200 So first we've got here dog with interpolation. 03:28.200 --> 03:32.520 Next up we've got now dog without any interpolation. 03:32.520 --> 03:34.950 That's why we see dollar name in here. 03:35.070 --> 03:35.970 So what. 03:36.000 --> 03:37.110 What's the difference. 03:37.110 --> 03:40.350 Why would you have two types of strings. 03:40.350 --> 03:47.130 Well theoretically this single quote string is faster as it has to do less. 03:47.130 --> 03:53.520 It doesn't have to look for variables, for expressions, and for special character combinations like 03:53.520 --> 03:54.990 new lines and tabs. 03:54.990 --> 04:05.910 Just be wary with trying to optimize or do micro-optimizations by always using single quotes first. 04:05.910 --> 04:10.950 Before you do any optimization, just make sure that you profile your code first. 04:10.950 --> 04:19.770 And I think that actually it's rather not possible that the type of strings you use would significantly 04:19.770 --> 04:23.820 improve performance or slow down your application.