将商品添加到购物车并更改数量显示以下错误.如何修复它

Question

注意:未定义索引:9781400108503在C:xampphtdocsibshelf.comcart.php on line 38

注意:未定义的索引:9781400108503在C:xampphtdocsibshelf.comcart.php上的第42行

警告:array_count_values():只能计数STRING和INTEGER值!C:xampphtdocsibshelf.comcart.php on line 53

// book_isbn got from form post method
if(isset($_POST['bookisbn'])){
$book_isbn = $_POST['bookisbn'];
}
if(isset($book_isbn))
{
// new item selected
if(!isset($_SESSION['cart']))
{
// $_SESSION['cart'] is associative array that bookisbn => qty
$_SESSION['cart'] = array();
$_SESSION['total_items'] = 0;
$_SESSION['total_price'] = '0.00';
}
if(!isset($_SESSION['cart'][$book_isbn]))
{
$_SESSION['cart'][$book_isbn] = 1;
} elseif(isset($_POST['cart']))
{
$_SESSION['cart'][$book_isbn]++;
unset($_POST);
}
}
// if save change button is clicked , change the qty of each bookisbn
if(isset($_POST['save_change'])){
foreach($_SESSION['cart'] as $isbn =>$qty){
if($_POST[$isbn] == '0')
{
unset($_SESSION['cart']["$isbn"]);
} else {
$_SESSION['cart']["$isbn"] = $_POST["$isbn"];
}
}
}
$title = "Your shopping cart";
if(isset($_SESSION['cart']) && (array_count_values($_SESSION['cart']))){
$_SESSION['total_price'] = total_price($_SESSION['cart']);
$_SESSION['total_items'] = total_items($_SESSION['cart']);

Answer 1

9781400108503"似乎是save_change for循环中$isbn的值

在第42行，为$_POST[$isbn]触发通知。确保使用isset($_POST[$isbn])。这个ISBN好像没有值。

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在第53行，您正在使用array_count_values()。这不是我们要用的函数。用count($_SESSION['cart'])代替。