Wordpress get menu list

$menu_name = 'primary';

    if ( ( $locations = get_nav_menu_locations() ) && isset( $locations[ $menu_name ] ) ) {
$menu = wp_get_nav_menu_object( $locations[ $menu_name ] );

$menu_items = wp_get_nav_menu_items($menu->term_id);

$menu_list = '<ul id="menu-' . $menu_name . '">';

foreach ( (array) $menu_items as $key => $menu_item ) {
$title = $menu_item->title;
$url = $menu_item->url;
$menu_list .= '<li><a href="' . $url . '">' . $title . '</a></li>';
}
$menu_list .= '</ul>';
    } else {
$menu_list = '<ul><li>Menu "' . $menu_name . '" not defined.</li></ul>';
    }
echo $menu_list;