array_search_string

function array_search_string($needle, array $haystack)
{

    $found = false;
    if (strpos($needle, '[') !== false) {
        $k = preg_split('~\]?\[~', substr($needle, 0, -1));
        $i = 1;
        $t = count($k);
        foreach ($k as $k) {
            if ((array)$haystack === $haystack) {
                if (array_key_exists($k, $haystack)) {
                    $haystack = $haystack[$k];
                    $i === $t && ($found = true);
                }
            }
            ++$i;
        }
    } elseif (array_key_exists($needle, $haystack)) {
        $haystack = $haystack[$needle];
        $found = true;
    } else {
        $haystack = null;
    }
    return $found ? $haystack : null;

}