WEBVTT 00:00.380 --> 00:00.740 Okay. 00:00.740 --> 00:04.520 So now let's see some data types in PHP in practice. 00:04.520 --> 00:09.890 And the first step is to create a types PHP file and then open it. 00:09.890 --> 00:12.320 And let's see some examples. 00:13.490 --> 00:20.240 So let's start by adding the PHP starting tag and define the is student variable. 00:20.240 --> 00:26.600 But this time let's not associate a boolean value with it, but instead a number. 00:26.600 --> 00:28.910 And also to output data. 00:28.910 --> 00:34.340 We're not going to use the echo statement, but a var dump function. 00:35.780 --> 00:42.470 So because we use vardump, we're not only going to see the value of the variable, but also its type. 00:42.470 --> 00:47.000 Like in this example that's an integer and the value is one. 00:48.830 --> 00:55.550 So next up something that you will often do with programming in general is you will make some conditions. 00:55.550 --> 00:59.870 And depending on those conditions something else would happen. 00:59.870 --> 01:06.940 So you will often check if the value of specific expression is either true or false. 01:06.970 --> 01:15.520 Now, fortunately, with this Vardump function, we can output multiple values by calling it just once 01:15.520 --> 01:17.530 by separating them with a comma. 01:17.560 --> 01:27.070 So now I can compare the student variable using the comparison operator which is two equality signs 01:27.070 --> 01:28.810 with true. 01:29.410 --> 01:31.030 Now let me run that. 01:31.030 --> 01:34.120 And the result of that is true. 01:34.150 --> 01:41.020 Now we see that if student is an integer and we are comparing it with true. 01:41.050 --> 01:49.030 Now if I would also dump the value of true, we can see that this is of type boolean. 01:49.060 --> 01:51.490 So those are different types. 01:51.490 --> 01:55.930 And what happened here is again type coercion. 01:55.930 --> 01:59.260 So PHP is trying to convert the types. 01:59.260 --> 02:06.060 So the whole expression here makes sense so that the values can be compared. 02:06.960 --> 02:14.970 Now you should know that in PHP every number that's non-zero will just evaluate to true. 02:14.970 --> 02:16.950 And this is often used. 02:16.950 --> 02:26.640 So if I for example check with minus one then this comparison is also true. 02:26.670 --> 02:33.780 But if is student is set to zero this is then false. 02:35.880 --> 02:39.210 Okay so let me change the value here to one. 02:40.140 --> 02:49.110 Now here in this comparison let's use a strict equality operator which is not two equal signs but three 02:49.140 --> 02:50.970 equal signs together. 02:50.970 --> 02:52.590 And let's run that. 02:53.670 --> 02:58.410 So as we see the result of this comparison is now false. 02:59.170 --> 03:01.510 And nothing else has changed. 03:01.510 --> 03:11.200 So that's another way of comparing values in PHP that just takes into account also the types of the 03:11.200 --> 03:14.230 two expressions on the left and on the right side. 03:15.430 --> 03:20.050 So with just two equality signs, the type coercion will happen. 03:20.050 --> 03:28.210 But if you use the strict equality operator, then you are also making sure that the two values, the 03:28.210 --> 03:36.520 two expressions are of the same exact type, and only then you verify if the value is identical. 03:37.600 --> 03:40.750 Okay, so next up let's see an example with an array. 03:40.780 --> 03:46.480 Let's define a variable called scores and an array starts with square brackets. 03:46.480 --> 03:48.790 And let's just put some values in there. 03:48.790 --> 03:51.670 This would be number 85 an integer. 03:51.670 --> 03:55.150 But obviously we want to make things complex. 03:55.150 --> 03:58.660 So the next value would be a string 90. 03:59.440 --> 04:06.490 Okay, now let's vardump the result of just summing up all those values. 04:06.910 --> 04:15.340 So the way you access elements in the array is if that's an indexed array and it is an indexed array 04:15.400 --> 04:19.030 I just use the indexes starting from zero. 04:19.630 --> 04:26.680 So I'm gonna just add the scores zero to scores index one. 04:28.150 --> 04:32.920 And as you see the result is 175. 04:32.920 --> 04:39.760 So the types were coerced or this is sometimes also called type juggling. 04:39.760 --> 04:43.570 So the types were coerced to an integer. 04:43.960 --> 04:44.740 Okay. 04:44.740 --> 04:47.770 So let's make it even more interesting. 04:47.770 --> 04:51.940 Let's add another value 95 and half. 04:51.970 --> 04:56.650 That is a float value floating point number. 04:56.860 --> 04:58.160 So let's add this. 04:58.160 --> 05:00.290 The index here would be two. 05:00.320 --> 05:03.500 So as I said we index from zero. 05:03.770 --> 05:06.230 Let's see what will happen now. 05:06.260 --> 05:08.810 So now the result is float. 05:08.810 --> 05:14.120 So as we see there is some precedence in what type is being used. 05:14.360 --> 05:22.850 If I remove this string and then I also need to get rid of this element. 05:22.880 --> 05:24.590 Let's see what will happen. 05:24.590 --> 05:27.890 So we also get the float as a result. 05:27.920 --> 05:36.680 Now what's interesting if I surround this float value in quotes in double quotes. 05:36.680 --> 05:44.300 So this is a string now and I add those two values I still get a float. 05:44.600 --> 05:55.010 So what we see here is just PHP is trying to guess what's the best type that it should be using to calculate 05:55.010 --> 05:58.070 something sensible from an expression. 05:59.150 --> 06:03.320 Now we can also vardump the scores array. 06:03.920 --> 06:06.590 So let's see how this would look like. 06:07.670 --> 06:10.010 So this is how the array would be outputted. 06:10.010 --> 06:14.030 We see that there is the index zero which contains an integer. 06:14.030 --> 06:18.620 And at index one we've got a string. 06:20.450 --> 06:25.940 So you can also influence the type of the value by typecasting. 06:25.970 --> 06:30.170 So in this example here let's have an output. 06:30.170 --> 06:33.590 Again we've got an array that has an integer. 06:33.590 --> 06:39.860 And the string though the result is float because it makes sense according to PHP. 06:39.890 --> 06:44.570 So I can do typecasting by using this int operator. 06:44.570 --> 06:49.400 And now I'm gonna first convert this element to an integer. 06:49.430 --> 06:51.320 Let's see what will happen then. 06:51.320 --> 06:54.860 So now in the array we've got two integers. 06:54.860 --> 07:01.770 This one and that one, so that the result of adding those is also an integer. 07:01.830 --> 07:09.960 Now keep in mind that this way here is just a way to cast to another type that might not be necessarily 07:09.960 --> 07:16.860 the best way to get an integer out of a floating point number, because you might want to apply different 07:16.860 --> 07:17.520 rules. 07:17.520 --> 07:22.590 And we're going to talk about that later on when I will talk more about numbers. 07:22.830 --> 07:25.950 For now, let's also see another example. 07:25.950 --> 07:28.710 This time we're going to use echo. 07:28.710 --> 07:38.130 And maybe here I'm just going to move those scores to the total variable and change it that way. 07:38.130 --> 07:42.300 So now that I can echo the value of total. 07:42.330 --> 07:45.180 So this would be total score is. 07:45.180 --> 07:48.840 And previously we have used the concatenation operator. 07:48.840 --> 07:50.400 So dot. 07:51.420 --> 07:55.410 So if I would like to uh sorry the name is Total. 07:55.410 --> 07:59.940 If I would like to output the score, I can do something like this. 07:59.940 --> 08:02.730 The total score is 180. 08:02.790 --> 08:05.760 I can also add a new line here. 08:08.250 --> 08:09.780 Like this. 08:09.780 --> 08:18.450 But what we can also do, and that only works with the double quotes, is I can just directly put a 08:18.450 --> 08:22.950 variable inside double quotes like this. 08:22.950 --> 08:28.110 As you see, even the code editor is highlighting this as something separate. 08:30.030 --> 08:33.150 And if I run this again, this also works. 08:33.150 --> 08:42.330 Now keep in mind that you can't put variables like that inside single quotes, because this would just 08:42.360 --> 08:44.580 output the name of the variable. 08:44.580 --> 08:49.050 And also special characters don't work within single quotes. 08:50.160 --> 08:51.270 So let's summarize. 08:51.270 --> 08:58.930 So in this video we talked about the type coercion, and I think it's super important to just realize 08:58.930 --> 09:05.140 how important concept this is, because it can really have some serious consequences. 09:05.140 --> 09:12.250 What we did here, by comparing just this variable value to true, is something that you're gonna do 09:12.250 --> 09:21.490 all the time, because those kind of comparisons are often used in control structures that decide the 09:21.490 --> 09:23.290 flow of the program. 09:23.290 --> 09:31.540 Now, if you wouldn't be aware of the implications of type coercion or just using the strict equality 09:31.540 --> 09:35.950 operators, then well, you just might get into trouble. 09:35.950 --> 09:43.870 So it's super important to just be aware of type coercion that we've also seen in this array example. 09:43.870 --> 09:54.100 And then we've also seen how you can explicitly cast one type to another by using the typecasting operator.