Online PHP editor | refs for Xv6Op

<?php $a = array('a' => 'a', 'b' => 'b', 'z' => array('c' => 'c', 'd' => 'd')); $b = array('a' => 'c', 'z' => array('c' => 'e')); $merge = function($a, $b) use ($merge){ if (is_array($a) && is_array($b)){ foreach ($b as $key => $value){ if (is_array($value) && isset($a[$key]) && is_array($a[$key])){ return $merge($a[$key], $value); } else { return $value; } } } else { return $b; } }; var_dump($merge($a, $b));