in_array_r() - a multidimensional version of PHP's in_array()

in_array_r()

function in_array_r($needle, $haystack, $strict = false) {
    foreach ($haystack as $item) {
        if (($strict ? $item === $needle : $item == $needle) || (is_array($item) && in_array_r($needle, $item, $strict))) {
            return true;
        }
    }
    return false;
}

Usage:

$multi_arr = array(array("foo", "bar"), array("baz", "qux"));
echo in_array_r("baz", $multi_array) ? 'found' : 'not found';

http://stackoverflow.com/a/4128377/1879895