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(         


        

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;
}