- array_splice: documentation ( source)
- array_slice: documentation ( source)
- print_r: documentation ( source)
- array_merge: documentation ( source)
<?php
$array = array(1 => 0, 2, 3, 4);
print_r($array);
array_splice($array, 3, count($array), array_merge(array('x'), array_slice($array, 3)));
print_r($array);
?>