Get keys from multidimensional array recursively

Question

I have multidimensional array like this. It is in var_dump() formatting.

array(1) {
  [4]=>
  array(1) {
    [2]=>
    array(1) {
      [5]=>
      arra         


        

Answer 1

This seems to work for me:

function array_keys_recursive(array $arr) {
    foreach($arr as $key => $value) {
        $return[] = $key;
        if(is_array($value)) $return = array_merge($return, array_keys_recursive($value));
    }
    return $return;
}

Basically identical to yours, which also works, by the way.