Page 82 - Beginning PHP 5.3

Part II: Learning the Language
Here ’ s a list of the comparison operators in PHP:

Operator Example Result

== (equal) $x == $y true if $x equals $y ; false otherwise
!= or < > (not equal) $x != $y true if $x does not equal $y ; false

otherwise
=== (identical) $x === $y true if $x equals $y and they are of the
same type; false otherwise

!== (not identical) $x !== $y true if $x does not equal $y or they are not
of the same type; false otherwise
< (less than) $x < $y true if $x is less than $y ; false otherwise

> (greater than) $x > $y true if $x is greater than $y ; false
otherwise

< = (less than or equal to) $x < = $y true if $x is less than or equal to $y ; false
otherwise
> = (greater than or equal to) $x > = $y true if $x is greater than or equal to $y ;
false otherwise

The following examples show comparison operators in action:
$x = 23;

echo ( $x < 24 ) . “ < br / > ”; // Displays 1 (true)
echo ( $x < “24 ” ) . “ < br / > ”; // Displays 1 (true) because
// PHP converts the string to an integer
echo ( $x == 23 ) . “ < br / > ”; // Displays 1 (true)
echo ( $x === 23 ) . “ < br / > ”; // Displays 1 (true)
echo ( $x === “23 ” ) . “ < br / > ”; // Displays “” (false) because
// $x and “23” are not the same data type
echo ( $x > = 23 ) . “ < br / > ”; // Displays 1 (true)

echo ( $x > = 24 ) . “ < br / > ”; // Displays “” (false)
As you can see, comparison operators are commonly used to compare two numbers (or strings
converted to numbers). The = = operator is also frequently used to check that two strings are the same.

Incrementing /Decrementing Operators
Oftentimes it ’ s useful to add or subtract the value 1 (one) over and over. This situation occurs so
frequently — for example, when creating loops — that special operators are used to perform this task:
the increment and decrement operators. They are written as two plus signs or two minus signs,

respectively, preceding or following a variable name, like so:
++$x; // Adds one to $x and then returns the result
$x++; // Returns $x and then adds one to it
– - $x; // Subtracts one from $x and then returns the result

$x – - ; // Returns $x and then subtracts one from it
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