SK3TCHY

The key thing to know is that you need give array_walk / array_walk_recursive an array

    function lets_walk() {
        $sweet = array('a' => 'apple', 'b' => 'banana');
        $fruits = array('sweet' => $sweet, 'sour' => 'lemon');
        array_walk_recursive($fruits, array($this, "walk_print"));
    }

    function walk_print($value, $key){
        print($value);
    }