- var_dump: documentation ( source)
- in_array: documentation ( source)
- define: documentation ( source)
<?php
define( TRUE, false );
$a = array( 'a', 'b' );
$d = array( 'c', 'b' );
$c = array( 'a' );
$p = in_array( $c, $a ) && !in_array( $c, $a );
var_dump( $p );
var_dump( TRUE == true );