<?php
$array = array (
'anteater',
'bear',
'cheetah',
);
function cmp($a, $b) {
return strlen($a) - strlen($b);
}
usort($array, 'cmp');
print_r($array);
?>
If the string you want to search are in a file, then:
$array = file('filename.txt', FILE_IGNORE_NEW_LINE);