Comparing Values

An operator is something that takes 1 or more values and yields another value. 0:00 I've shown you several different operators so far. 0:05 The assignment operator uses the equal sign to put a value into a variable. 0:08 The arithmetic operators let you add, subtract, divide, and multiply numbers. 0:14 And the concatenation operators let you create a new string 0:19 by combining several strings together. 0:23 Next we'll be looking at comparison operators for equality. 0:26 Comparison operators do exactly what they sound like. 0:31 They allow us to compare values and yield the result. 0:34 There are quite a few comparison operators, and 0:38 we'll cover them all in a later course. 0:40 I have included more information in the teacher's notes, 0:42 if you want to learn more now. 0:44 For this course, we'll be looking at equal and identical comparisons. 0:46 Equal compares only the value, while identical compares the value and the type. 0:51 We've looked at the number of different variable types in PHP including 0:57 integers floats strings and booleans. 1:01 PHP is called a weakly or loosely typed language. 1:04 This means that, generally, you don't need to specify the type you'll be using. 1:08 PHP will automatically assign the type for 1:13 you based on the value inside the variable. 1:15 This also means that PHP will attempt 1:19 to juggle the types to work within the situation in which they're being used. 1:22 We saw this when working with number variables. 1:27 When you were using the plus sign to add two variables 1:30 PHP assumes that those values should be evaluated as numbers. 1:33 Type juggling can be helpful when accepting data 1:38 from sources beyond your control like user data from a web form. 1:41 Values submitted from an online form are collected as a string, but 1:45 they can be used in a calculation because of Type Juggling. 1:49 Let's comment out 1:54 these output lines. 1:59 Then let's start with something simple. 2:04 We'll add var_dump(1 + "2"). 2:06 Now let's run our script. 2:14 Since we're using an addition operator, 2:16 when we run our program PHP juggles the string 2 to an integer and 2:20 adds 1 + 2, which gives us the integer 3 as the result. 2:26 So now let's take a look at the comparison operator. 2:31 We'll start by creating two variables, 2:34 a = 10 and b = 10. 2:39 Then we can compare these variables as equal and 2:43 use our var_dump to display the results. 2:46 When we run the script, 2:57 we see that the evaluation is true because both values equal 10. 2:59 If we want to compare if these variables are identical, meaning that 3:03 the value is the same and also the type is the same we use the triple equals. 3:08 When we run the script now, we see that the evaluation is false, 3:20 because a and b are not the same type. 3:24 We can also use these to compare strings. 3:28 We'll var_dump again, and 3:31 then we'll compare string_one 3:36 to be equal to learning to display 3:41 Hello Alena to the screen. 3:46 Let's uncomment this line to echo out our string, so 3:54 we can see what that looks like. 3:58 Great. 4:03 Well, let's also comment about these //var_dumps. 4:05 There we go. 4:11 That should make our output a little easier to read. 4:11 Our result of string one isn't exactly the same, 4:16 because we have I am in front, and we also have a new line. 4:19 So the VAR dump evaluates to the bullion false. 4:25 Let's update the string one value and remove the new line and 4:27 prepend string using our comments. 4:32 Not this or this. 4:37 Now let's run our script again. 4:42 Great, now our var dump evaluates to true. 4:44 Even though string one uses the name variable, the values are the same. 4:47