PHP: Boolean

True and False

true and false are built-in boolean type. Case does not matter. true is the same as True.

The following are all FALSE:

• the integer 0 (zero)
• the float 0.0 (zero)
• the empty string "", and the string "0"
• array with zero elements
• object with zero member variables (PHP 4 only)
• the special type NULL (including unset variables)
• SimpleXML objects created from empty tags

Example:

<?php
$x = 4;
if ($x == 4) {echo "yay";} else {echo "nay";} # yay
if (true) {echo "yay";} else {echo "nay";} # yay
if (trUe) {echo "yay";} else {echo "nay";} # yay
?>