Now that you've got the basics of PHP variables and operators down, the second article in this series takes a look at PHP's form-processing capabilities, and introduces you to the comparison and logical operators and the "if-else" and "switch" family of conditional statements.

Of course, the example you've just seen is very rudimentary. To really add some punch to it, you need to know how to construct what the geeks call a conditional statement. And the very basis of a conditional statement is comparison - for example, "if this is equal to that, do thus and such".

PHP comes with a bunch of useful operators designed specifically for use in conditional statement. Here's a list:

Assume $delta = 12 and $omega = 9

Operator

What It Means

Expression

Evaluates To

==

is equal to

$delta == $omega

False

!=

is not equal to

$delta != $omega

True

>

is greater than

$delta > $omega

True

<

is less than

$delta < $omega

False

>=

is greater than or equal to

$delta > = $omega

True

<=

is less than or equal to

$delta <= $omega

False

PHP4 also introduces a new operator, which tests both for equality and type: the === operator. There's a simple illustration of this on the last page.