在不使用PHP的情况下计算foreach循环中的会话

Question

I am trying to count all my products that is stored in a session called $_SESSION['product'.$id];. But its not counting, its counting like this 1 1 1 1. So its counting 1 of each product id separated. My foreach loop...

foreach ($_SESSION as $name => $value) {
    if($value > 0){
        if(substr($name, 0, 8 ) == "product_"){
            $length = strlen($name) -8;
            $item_id = substr($name,8 , $length);

            $query = "SELECT * 
                 FROM gallery2 
                 WHERE gallery2.id =".escape_string($item_id). "";
            $run_item = mysqli_query($conn,$query);
            while($rows = mysqli_fetch_assoc($run_item)){ 
                $vari   = $rows['variante'];
                $num    = $rows['title'];
                $id     = $rows['id'];

                if(!isset($_SESSION['icms'.$id])) {
                    $_SESSION['icms'.$id]='0';
                }else{
                    $_SESSION['icms'.$id];
                }

                //some code here

                $subtotal=$value * $_SESSION['icms'.$id];
                $cost=$_SESSION['icms'.$id];

                $product = '
        <tr>
          <td style="width:100px; "><img src="../'.$rows['image'].'" style="width:90%;border: 1px solid black;"></td>
          <td>'.$num.''.$vari.'</td>
          //some code here
          <td class="product'.$id.'">'.$value.'</td>
          <td class="cost" data-id="'.$id.'" >R$:'.$cost.'</td>
          <td class="subtotal" data-id="'.$id.'">R$:'.number_format($subtotal, 2, '.', '') .'</td>
          <td> 
             '.$btn_add.' '.$btn_remove.' '.$btn_delete.'
          </td>
        </tr>';
                echo $product;  
                //some closing brackets 

Why this is happening? What i tried:

print_r(count($_SESSION['product_'.$item_id])) ;
print_r(count($name)) ;
print_r(count($product)) ;
print_r(count($value)) ;

Answer 1

You can use this:

$product_count = count(array_filter(array_keys($_SESSION), function($x) {
    return substr($x, 0, 8) == 'product_';
}));

But as I mentioned in a comment, it would probably be better if you redesigned your data. Instead of storing each product in a separate session variable, store them in an array. So instead of $_SESSION['product_'.$i] you would have $_SESSION['products'][$i]. Then you wouldn't need the code that checks whether the session variable beings with product_, you could just use

foreach ($_SESSION['products'] as $id => $value)

And to get the number of products, it would just be count($_SESSION['products']).