- print_r: documentation ( source)
- array_diff: documentation ( source)
<?php
$array1 = array("a" => "green", "b" => "yellow", "c" => "reds");
$array2 = array("a" => "green", "b" => "yellow", "c" => "red");
$result = array_diff($array1, $array2);
print_r($result);
?>