Use http://us2.php.net/manual/en/function.usort.php
with this custom function
function sort($a,$b){
return strlen($b)-strlen($a);
}
usort($array,'sort');
Use uasort if you want to keep the old indexes, use usort if you don’t care.
Also, I believe that my version is better because usort is an unstable sort.
$array = array("bbbbb", "dog", "cat", "aaa", "aaaa");
// mine
[0] => bbbbb
[1] => aaaa
[2] => aaa
[3] => cat
[4] => dog
// others
[0] => bbbbb
[1] => aaaa
[2] => dog
[3] => aaa
[4] => cat