You cannot sort an simple array by his key in cake. You can only sort like this: (or you can use {n}.{n} )
$array = (e,h,u,w,r);
$result = Set::sort($array, '{n}', 'asc');
pr($result);
For key sorting use ksort php function, or create in cake a ksort function with same properties and use it
ksort( $array );
foreach ( $array as $key => $val ) {
print "$key = $val<br />";
}
solved Using Cake PHP Sort to sort Array Keys