How to check if an array is empty in PHP? Simple and correct ways

Hello everyone! I just started learning PHP and encountered this task: I need to check if an array is empty before outputting its contents. I tried several methods, but I'm not sure which one is correct and reliable. Here's an example. I have an array of products in the cart: ```php $cart = []; // or $cart = ['item1', 'item2']; ``` I want to do a check: if the cart is empty, show the message "Cart is empty", otherwise — display the products. I tried using `empty()`: ```php if (empty($cart)) { echo "Cart is empty"; } ``` But I heard that `empty()` might not work exactly as I think. I also saw in someone else's code `count($cart) == 0` and `sizeof($cart) == 0`. Which method is better? Does it account for the case when the array is not declared? Or when the array has keys