WEBVTT 00:00.170 --> 00:07.370 Next up, we can use an enum keyword to define an enum or enumeration. 00:07.940 --> 00:18.170 Then you can add cases to add specific possible values of this enum, like days of the week. 00:18.200 --> 00:26.390 And what this does is we create a type safe way to represent some set of values. 00:26.420 --> 00:31.010 Now let's see how can you use an enum to assign it to a variable? 00:31.070 --> 00:38.510 We're going to use the name of the enum double colon operator and just choose one of the options like 00:38.510 --> 00:39.470 Wednesday. 00:39.500 --> 00:41.660 So enums are also classes. 00:41.660 --> 00:46.790 So we always use the enum values using the enum or class name. 00:46.970 --> 00:54.560 The double colon operator and one of the options and today variable is now of the type. 00:54.590 --> 00:56.180 Days of the week. 00:56.180 --> 00:59.870 That's not a string and not an integer. 01:01.100 --> 01:08.840 If you would like to then compare the value to one of the enum values you use strict equality operator. 01:08.840 --> 01:15.680 So three equal signs and you need to compare it to one of the possible values. 01:17.930 --> 01:24.830 Like Wednesday here we can confirm it is Wednesday. 01:27.740 --> 01:30.680 So that's a type safe comparison. 01:30.680 --> 01:36.020 And PHP will make sure we are actually comparing the same type. 01:36.050 --> 01:38.150 Let's define another enum. 01:38.150 --> 01:45.230 This time it would be a color and enums can have a so-called backing. 01:45.230 --> 01:49.640 So backing is defining this optional values. 01:49.670 --> 01:54.770 Now let me show you how do you read those values which can be strings or integers. 01:54.770 --> 02:04.040 So if specific variable has the value of one of those constants from the enum, you can also get the 02:04.040 --> 02:05.660 actual value from it. 02:08.920 --> 02:16.120 So if the color is red to read the value, you're going to use the arrow operator. 02:16.120 --> 02:19.840 And this should display this backing value. 02:19.870 --> 02:22.660 I think I've used the wrong class name here. 02:22.660 --> 02:23.920 Let's fix that quickly. 02:23.920 --> 02:27.310 And now let's run that. 02:28.210 --> 02:29.320 So there it is. 02:29.380 --> 02:32.980 The comparison works fine. 02:32.980 --> 02:36.910 And also we've got the value of an enum this way. 02:37.060 --> 02:40.870 Now you can use enums for type hinting. 02:41.710 --> 02:46.810 Let's say we have an is weakened function. 02:46.810 --> 02:51.070 We can type in the argument using days of week. 02:52.780 --> 03:03.430 This would return a boolean, and the logic would be whether the day is exactly days of week Saturday 03:04.330 --> 03:11.470 or the day is exactly days of week Sunday. 03:12.340 --> 03:13.720 Let's test this. 03:13.720 --> 03:15.910 So we run this weekend. 03:16.960 --> 03:25.360 Maybe I'm gonna run this for Monday, and I'm going to use the ternary operator to display either yes 03:25.390 --> 03:27.490 or no. 03:27.490 --> 03:30.610 And finally let's run it. 03:30.610 --> 03:32.680 So the answer is no here okay. 03:32.680 --> 03:36.250 So to summarize enums they are not really complicated. 03:36.250 --> 03:41.200 They let you create a new type with some fixed set of possible values. 03:41.200 --> 03:43.720 And they provide type safety. 03:43.720 --> 03:49.330 And this basically prevents you from invalid values being used. 03:49.330 --> 03:52.750 The values you didn't expect to be used. 03:52.750 --> 04:00.550 Your code might be cleaner, more self-documenting you can have the backup values that might have some 04:00.550 --> 04:02.050 more meaning. 04:02.050 --> 04:11.410 You can use enums in type hints, and generally they will probably let you prevent some errors and make 04:11.410 --> 04:16.240 your code more readable and easier to understand.