Assignment Operators
The basic assignment operator is "=". Your first inclination might be to think of this as "equal to". Don't. It really means that the left operand gets set to the value of the expression on the rights (that is, "gets set to").
The value of an assignment expression is the value assigned. That is, the value of "$a = 3" is 3. This allows you to do some tricky things:
for e.g
PHP Code:
<?php
$a = ($b = 4) + 5; // $a is equal to 9 now, and $b has been set to 4.
?>