WEBVTT 00:00.470 --> 00:05.480 So next up, let's see how can we search and replace text in PHP. 00:05.510 --> 00:08.450 Let me define a haystack variable. 00:08.540 --> 00:14.060 That's a name that's often used for the string you're going to be searching in. 00:14.060 --> 00:20.480 And let's use a typical text which is the quick brown fox. 00:22.640 --> 00:23.180 Okay. 00:23.180 --> 00:29.360 Um, first let's see how can we get a position of a specific substring in a haystack? 00:30.800 --> 00:32.660 Let me define the post variable. 00:32.660 --> 00:37.340 And the Strpos function is going to give you this. 00:37.340 --> 00:42.920 So first you need to point to the haystack which is the string we're going to be searching in. 00:42.920 --> 00:46.970 And then the text that you want found. 00:48.890 --> 00:56.090 So now I dump this and we can see what's the position of this specific string fragment. 00:58.430 --> 01:01.010 Um let me try again. 01:01.010 --> 01:03.350 String search okay. 01:03.380 --> 01:10.450 So the position is four, Now, which is 01234. 01:10.450 --> 01:12.610 So it is zero indexed. 01:13.390 --> 01:13.600 Okay. 01:13.630 --> 01:16.330 Now let's see how can we replace the text. 01:16.330 --> 01:21.190 So let's maybe immediately vardump this without using any variables. 01:21.190 --> 01:24.430 So there is this str replace function. 01:25.150 --> 01:32.020 So I can replace maybe the text quick with a lazy. 01:32.470 --> 01:34.990 And I'm passing the haystack. 01:35.380 --> 01:38.470 And now let's run this. 01:39.820 --> 01:42.220 So this is how the text looks like. 01:42.220 --> 01:45.010 So this function is returning the new string. 01:45.010 --> 01:49.090 It's not doing anything to the original variable. 01:50.770 --> 01:54.520 Now also PHP supports the regular expressions. 01:54.520 --> 01:58.210 So regular expressions are not unique to PHP. 01:58.240 --> 02:00.280 That's a generic concept. 02:00.280 --> 02:06.190 And regular expressions let you match text using patterns. 02:06.190 --> 02:13.290 This means you are not searching for or replacing the literal text like in this case. 02:13.320 --> 02:19.380 Instead, you can provide a pattern and this pattern is evaluated. 02:19.380 --> 02:24.810 It's like a mini programming language inside a programming language. 02:25.140 --> 02:25.800 Maybe. 02:25.800 --> 02:27.480 Let's just see an example. 02:27.780 --> 02:35.220 So there are some specific functions like Prague match or Prague match or which we're going to use. 02:35.220 --> 02:44.460 This specific one will match all the instances of a specific pattern that can be found in a haystack, 02:44.760 --> 02:47.610 and you just need to pass it a variable. 02:47.610 --> 02:50.520 And this one is passed by reference. 02:50.610 --> 02:56.760 So we talked about references and how this function works is it will fill up. 02:56.760 --> 03:05.460 This matches variable with all the instances found based on this pattern that you provide here. 03:05.460 --> 03:08.820 So the regular expression needs two slashes. 03:08.820 --> 03:12.480 And then inside you can use some special symbols. 03:12.480 --> 03:22.510 So for example slash w means any character That is a word character that's an uppercase lowercase letter. 03:22.540 --> 03:25.000 Underscore and numbers. 03:25.090 --> 03:29.470 Next we've got quantifiers inside curly braces. 03:29.470 --> 03:34.360 I can say match all those characters that you have before. 03:34.360 --> 03:38.110 So this is a single word character five times. 03:38.110 --> 03:47.830 And since I'm running Pregmatch, all this will find all the instances of basically words that are, 03:48.550 --> 03:52.210 well, that length is five characters. 03:52.210 --> 03:55.210 So we are searching inside this text. 03:55.930 --> 04:02.410 This means I expect to find two words the quick and brown. 04:03.250 --> 04:04.420 So let me run this. 04:04.420 --> 04:09.580 Now the file is string search. 04:10.870 --> 04:14.260 Yeah, so I forgot to vardump this. 04:14.350 --> 04:21.220 So let's vardump matches and rerun that again. 04:22.030 --> 04:22.540 There it is. 04:22.540 --> 04:24.580 We've got quick and brown.