如何在另一个页面中访问PHP会话变量？

Question

I have this shopping cart page coded, but i am clueless about how to acces the product id from session in another page? Anyone please help me! I'm beginner so if you please give me example code too it'd help me a lot.

<?php
    session_start();
    $product_ids = array();
//session_destroy();

//check if Add to Cart button has been submitted
if(filter_input(INPUT_POST, 'add_to_cart')){
    if(isset($_SESSION['shopping_cart'])){

        //keep track of how mnay products are in the shopping cart
        $count = count($_SESSION['shopping_cart']);

        //create sequantial array for matching array keys to products id's
        $product_ids = array_column($_SESSION['shopping_cart'], 'id');

        if (!in_array(filter_input(INPUT_GET, 'id'), $product_ids)){
        $_SESSION['shopping_cart'][$count] = array
            (
                'id' => filter_input(INPUT_GET, 'id'),
                'name' => filter_input(INPUT_POST, 'name'),
                'price' => filter_input(INPUT_POST, 'price'),
                'quantity' => filter_input(INPUT_POST, 'quantity')
            );   
        }    
    }
    else { //if shopping cart doesn't exist, create first product with array key 0
        //create array using submitted form data, start from key 0 and fill it with values
        $_SESSION['shopping_cart'][0] = array
        (
            'id' => filter_input(INPUT_GET, 'id'),
            'name' => filter_input(INPUT_POST, 'name'),
            'price' => filter_input(INPUT_POST, 'price'),
            'quantity' => filter_input(INPUT_POST, 'quantity')
        );
    }
}
?>

Answer 1

Use the same code you have here on the other page to get the product_ids

//other page
session_start();
$product_ids = array_column($_SESSION['shopping_cart'], 'id');