Wordpress menus via Functions

custom-menu.php

$menu_exists = wp_get_nav_menu_object( 'custom-menu');

// If it doesn't exist, let's create it.
if( !$menu_exists){
	register_nav_menus(
		array(
			'custom-menu' => 'Mi Custom Menú',
		)
	);
    $menu_id = wp_create_nav_menu('Mi Custom Menú');
wp_update_nav_menu_item($menu_id, 0, array(
 	'menu-item-title' =>  __('Item 1'),
 	'menu-item-url' => home_url( '/item-1' ),
    'menu-item-status' => 'publish'));
wp_update_nav_menu_item($menu_id, 0, array(
 	'menu-item-title' =>  __('Item 2'),
 	'menu-item-url' => home_url( '/item-2' ),
    'menu-item-status' => 'publish'));
}
if ( $menu_id > 0 ) {
		// set our new MENU up at our theme's nav menu location
		set_theme_mod( 'nav_menu_locations' , array( 'custom-menu' => 'Mi Custom Menú' ) );
		// add a menu item to that new menu
	}
 //end custom menu