PHP best way to MD5 multi-dimensional array?

Question

What is the best way to generate an MD5 (or any other hash) of a multi-dimensional array?

I could easily write a loop which would traverse through each level of the

Answer 1

// Convert nested arrays to a simple array
$array = array();
array_walk_recursive($input, function ($a) use (&$array) {
    $array[] = $a;
});

sort($array);

$hash = md5(json_encode($array));

----

These arrays have the same hash:
$arr1 = array(0 => array(1, 2, 3), 1, 2);
$arr2 = array(0 => array(1, 3, 2), 1, 2);