How to access and manipulate multi-dimensional array by key names / path?

Question

I\'ve to implement a setter in PHP, that allows me to specify the key, or sub key, of an array (the target), passing the name as a dot-separated-keys value.

Answer 1

This function does the same as the accepted answer, plus is adds a third parameter by reference that is set to true/false if the key is present

function drupal_array_get_nested_value(array &$array, array $parents, &$key_exists = NULL) {
  $ref = &$array;
  foreach ($parents as $parent) {
    if (is_array($ref) && array_key_exists($parent, $ref)) {
      $ref = &$ref[$parent];
    }
    else {
      $key_exists = FALSE;
      $null = NULL;
      return $null;
    }
  }
  $key_exists = TRUE;
  return $ref;
}