通过引用重新设置多维数组中的数组键，递归

Question

I want to reset keys in a big, multidimensional array. I already found a solution which is actually work:

$fix_keys = function(array $array) use (&$fix_keys)
{
    foreach($array as $k => $val)
    {
        if (is_array($val))
        {
            $array[$k] = $fix_keys($val);
        }
    }
    return array_values($array);
};

and the problem is, if I pass big arrays to it, it becomes slow and memory consuming. What about refactoring with working references:

$fix_keys = function(array &$array) use (&$fix_keys)
{
    foreach($array as $k => &$val)
    {
        if (is_array($val))
        {
            $array[$k] = $fix_keys($val);
        }
    }
    unset($val);
    $array = array_values($array);
};

but it messed up the array, all I get is [0] => null. What is wrong?

Edit: so input data:

$a = [
    'a' => 1,
    'b' => 2,
    'c' => [
        'aa' => 11,
        'bb' => [
            'ccc' => 1
        ],
        'cc' => 33
    ]
];

and I want to have:

array(3) {
  [0]=>
  int(1)
  [1]=>
  int(2)
  [2]=>
  array(3) {
    [0]=>
    int(11)
    [1]=>
    array(1) {
      [0]=>
      int(1)
    }
    [2]=>
    int(33)
  }
}

Answer 1

If memory is an issue you can try using yield. I'm not sure if this fits your needs, but here it is:

function reduce($array){
  foreach($array as $key => $value){
    if(is_array($value)){
      reduce($value);
    }
  }

  yield array_values($array);
}

---

You can also use send if you need to apply some logic to the generator.