WEBVTT 00:00.440 --> 00:00.800 Okay. 00:00.800 --> 00:03.650 So let's learn about the union type. 00:04.460 --> 00:07.070 So we're going to learn with functions. 00:07.070 --> 00:10.370 So let's create a union PHP file. 00:10.370 --> 00:14.270 And let's explain what it is all about. 00:14.900 --> 00:18.050 So as usual we're going to create a function. 00:18.860 --> 00:22.670 So let me call this process input. 00:23.270 --> 00:30.650 And the thing is that the input the argument it can take different types. 00:30.650 --> 00:35.210 So first let's declare the strict types here. 00:37.580 --> 00:38.540 Like this. 00:38.540 --> 00:41.990 And let me add the function body. 00:42.560 --> 00:48.200 So the input I'd like it to be either integer but also float and string. 00:48.440 --> 00:52.370 How can we achieve that if I've already typed that as int? 00:52.370 --> 00:56.060 Well this is where union types are for. 00:56.990 --> 00:58.220 So I use this. 00:58.250 --> 01:02.380 Let's call it pipe Type character or alternative character. 01:02.380 --> 01:06.160 And this way I just define alternative types. 01:06.190 --> 01:11.380 So if I want int, float and string, this is how I do that now. 01:11.410 --> 01:15.010 All those types can be passed to this function. 01:15.010 --> 01:23.440 But if I need to then work with this data that is being passed, it's my job to just check what's the 01:23.440 --> 01:24.040 type. 01:24.070 --> 01:26.680 Obviously if I need this information. 01:27.340 --> 01:34.000 Next up, depending on the type of the passed argument, we'd like to pass it through some different 01:34.000 --> 01:35.740 processing rules. 01:35.740 --> 01:42.850 And maybe let's again use the match expression after we initially explained it. 01:42.850 --> 01:45.760 I don't think we have ever used it again. 01:45.760 --> 01:48.250 So let me show you something. 01:48.250 --> 01:53.470 So we can use match expression by just matching the true value. 01:53.470 --> 02:02.100 So then in every individual case, I can actually call any function Like I can call the is int function 02:02.100 --> 02:13.830 to check if the input is an integer, and then I can output something something like integer and concatenate 02:14.130 --> 02:16.740 the input text. 02:16.770 --> 02:19.830 Maybe I will just multiply this integer. 02:19.950 --> 02:25.650 Next up I'm gonna check if it is a float. 02:26.970 --> 02:37.320 Then we're gonna return the text float and concatenate that with rounding the input. 02:38.640 --> 02:42.570 And finally let's check if it is a string. 02:42.570 --> 02:49.830 So if input is a string then we are just outputting that it is a string. 02:49.830 --> 02:53.370 And maybe let's cast it to uppercase. 02:53.370 --> 02:59.860 So we use the str to upper function On the input. 03:02.080 --> 03:07.240 And the default case would be we just output unknown type. 03:07.600 --> 03:15.160 Now that is an interesting use case for the match expression because we are matching true and we want 03:15.160 --> 03:18.490 to match it to a case that will also return true. 03:18.550 --> 03:26.800 Now all of those cases can't return true because the argument can't be integer, float, and string 03:26.800 --> 03:31.510 at the same time, or it can't be none of those at the same time. 03:31.780 --> 03:37.840 So it's actually only possible to match one of those cases to true. 03:37.870 --> 03:44.020 So that just might be an not really obvious use case for the match expression. 03:44.740 --> 03:44.920 Okay. 03:44.950 --> 03:47.800 So now let's use this function for something. 03:47.800 --> 03:51.430 Let's define an array with different values. 03:51.670 --> 03:56.740 So an integer float value a string. 03:56.740 --> 04:07.030 Another integer, maybe another float value, and finally a string. 04:08.080 --> 04:13.540 And then let's use a loop to go over all the elements. 04:15.430 --> 04:20.260 That's inputs as input. 04:22.150 --> 04:30.070 And for every single one of those elements from the array, let's just echo the output of process input, 04:30.490 --> 04:31.900 passing the input. 04:31.900 --> 04:35.860 And let's just concatenate that with a new line. 04:35.860 --> 04:38.200 And I think it's time to run it. 04:38.200 --> 04:48.580 I run the union PHP and this is our output, which basically just confirms that this function can work 04:48.580 --> 04:49.750 with union types. 04:49.750 --> 04:51.430 And also as a summary. 04:51.580 --> 04:53.980 That's just the way you define union types. 04:53.980 --> 04:56.860 If obviously you have a need for that.