Why not try this:

PHP:

Single dimensional-
$arr['short']  = 'val';
$arr['longkey'] = 'val';

Multi dimensional-

$arr[0][0]='00';
$arr[0][1]='01';
$arr[1][0]='10';
$arr[1][1]='11';

This looks neat,structured & easy to understand what key holds what value.