PHP: Merge Multidimensional Array

merge-md.php

<?php
function array_merge_value_md(array &$array1, array &$array2)
    {
        $merged = $array1;
        foreach ($array2 as $key => &$value) {
            if (is_array($value) && isset($merged[$key]) && is_array($merged[$key])) {
                $merged[$key] = array_merge_value_md($merged[$key], $value);
            } else {
                $k = array_search($value, $merged);
                if ($k !== false) {
                    $merged[$k] = $value;
                } else {
                    if (is_string($key)) {
                        $merged[$key]  = $value;
                    } else {
                        $merged[]  = $value;
                    }
                }
            }
        }
        return $merged;
    }