How to replace key in multidimensional array and maintain order

Question

Given this array:

$list = array(
   'one' => array(
       'A' => 1,
       'B' => 100,
       'C' => 1234,
   ),
   'two' => array(
       'A' => 1,
       'B' => 100,
       'C' => 1234,
       'three' => array(
           'A' => 1,
           'B' => 100,
           'C' => 1234,
       ),
       'four' => array(
           'A' => 1,
           'B' => 100,
           'C' => 1234,
       ),
   ),
   'five' => array(
       'A' => 1,
       'B' => 100,
       'C' => 1234,
   ),
);

I need a function(replaceKey($array, $oldKey, $newKey)) to replace any key 'one', 'two', 'three', 'four' or 'five' with a new key independently of the depth of that key. I need the function to return a new array, with the same order and structure.

I already tried working with answers from this questions but I can't find a way to keep the order and access the second level in the array:

Changing keys using array_map on multidimensional arrays using PHP

Change array key without changing order

PHP rename array keys in multidimensional array

This is my attempt that doesn't work:

function replaceKey($array, $newKey, $oldKey){
   foreach ($array as $key => $value){
      if (is_array($value))
         $array[$key] = replaceKey($value,$newKey,$oldKey);
      else {
         $array[$oldKey] = $array[$newKey];    
      }

   }         
   return $array;   
}

Regards

Answer 1

This function should replace all instances of $oldKey with $newKey.

function replaceKey($subject, $newKey, $oldKey) {

    // if the value is not an array, then you have reached the deepest 
    // point of the branch, so return the value
    if (!is_array($subject)) return $subject;

    $newArray = array(); // empty array to hold copy of subject
    foreach ($subject as $key => $value) {

        // replace the key with the new key only if it is the old key
        $key = ($key === $oldKey) ? $newKey : $key;

        // add the value with the recursive call
        $newArray[$key] = replaceKey($value, $newKey, $oldKey);
    }
    return $newArray;
}