我如何从基于PHP会话的数组中回显项目的总数。

Question

i cant for the life of me understand how i get the total amount of items. i've been following this tutorial to set up a webshop. http://jameshamilton.eu/content/simple-php-shopping-cart-tutorial

and everything seems to work within the tutorial. But i need to add the total number of items to my shopping cart. the code is creating an array with an id and quantity-number as an array stored within SESSION['cart'] . i have been messing around with the FOREACH code, but i only either get the total number of one of the items in the cart, og the total number of arrays. but i need the sum of the total quantity numbers, not the sum of rows.

any help in the right direction is much appreciated.

the working code:

$product_id = $_GET[id];     //the product id from the URL 
$action     = $_GET[action]; //the action from the URL
if($product_id && !productExists($product_id)) {
   die("Error. Product Doesn't Exist");
}
switch($action) {   //decide what to do
case "add":
$_SESSION['cart'][$product_id]++; //add one to the quantity of the product with id $product_id 
break;
case "remove":
$_SESSION['cart'][$product_id]--; //remove one from the quantity of the product with id $product_id 
if($_SESSION['cart'][$product_id] == 0) unset($_SESSION['cart'][$product_id]);
break;
case "empty":
unset($_SESSION['cart']); //unset the whole cart, i.e. empty the cart. 
break;
}


if($_SESSION['cart']) { //if the cart isn't empty
//show the cart
echo "<table border='1' padding=\"3\" width=\"40%\">";
   foreach($_SESSION['cart'] as $product_id => $quantity) {
   $sql = sprintf("SELECT productName, productImg, price FROM products WHERE id = %d;", $product_id);
$result = mysql_query($sql);
if(mysql_num_rows($result) > 0) {
list($productName, $productImg, $price) = mysql_fetch_row($result);
$arrayquantity = is_array($_SESSION['cart']) ? count($_SESSION['cart']) : 0;
$line_cost = $price * $quantity;        //work out the line cost
$total = $total + $line_cost;           //add to the total cost
}else{
//you have no items
}
function productExists($product_id) {
$sql = sprintf("SELECT * FROM products WHERE id = %d;", $product_id); 
return mysql_num_rows(mysql_query($sql)) > 0;
}

i have tried the following but it just results in "0"

if(isset($_SESSION['cart']) AND is_array(@$_SESSION['cart'])){
   foreach($_SESSION['cart'] AS $itemquantity){
   $totalquantity = $totalquantity + $itemquantity['quantity'];
   }
}
else{
$totalquantity = 0;
}
echo $totalquantity;

Answer 1

Try something like:

  if(isset($_SESSION['cart']) && is_array($_SESSION['cart'])) {
        $totalquantity = 0;
        foreach($_SESSION['cart'] AS $productId => $itemQuanity) {
            $totalquantity = $totalquantity + $itemQuanity;
        }
  }
  else {
       $totalquantity = 0;
  }
  echo $totalquantity;

You can replace foreach($_SESSION['cart'] AS $productId => $itemQuanity){ with foreach($_SESSION['cart'] AS $itemQuanity){ because you dont have need for key(here key is product id).

Answer 2

couple of changes: AND is logical, u need to use && for conditional check. also, is_array() shouldn't have a @ in the parameter.

   if(isset($_SESSION['cart']) && is_array($_SESSION['cart'])){ //change this line
     $totalquantity = 0;
     foreach($_SESSION['cart'] AS $itemquantity){
       $totalquantity +=  $itemquantity['quantity']; // and this line, just shorthand of ur line
      }
      }
     else{
     $totalquantity = 0;
     }
     echo $totalquantity;