How can I add elements to an empty array in PHP?

If I define an array in PHP such as (I don't define its size): <!-- language: lang-php --> $cart = array(); Do I simply add elements to it using the following? <!-- language: lang-php --> $cart[] = 13; $cart[] = "foo"; $cart[] = obj; Don't arrays in PHP have an add method, for example, `cart.add(13)`?