PHP 101 (Part 2) - Shakespeare's Rose - Operating With Extreme Caution (
Page 4 of 9 )
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.