Array case change?

Question

PHP

Hello!
There is a large multidimensional array, with names in upper case.
How can I change all data to lowercase?
Option array_map('strtolower', $array) - not suitable, because the array is large.

Answer 1

array array_change_key_case ( array $array [, int $case = CASE_LOWER ] )

Answer 2

array_walk_recursive($array, function(&$item) {
  $item = strtolower($item);
});

Answer 3

There is no other way, only this function or cycle