@smp_info
I think you are still tired. What would be wrong with:
<?php
$array = array('one', 'two', 'three', 'four');
//pop the last element off
array_pop($array);
//$array == array('one', 'two', 'three');
?>
As the documentation clearly notes, array_pop() not only returns the last element, but actually removes it from the array wich is passed by reference. Calling array_diff is a waste of resources.