在php购物车中找不到数组项目

Question

I am struggling with a weird situation here with arrays in PHP. I am trying to create a simple cart using a session variable.

Problem:

When the cart is empty, the program creates a new product with the itemid and qty variables when a product is added to cart (as required). It also does same when other new products are added.

It also is able to update the quantity of products if added again (as required).

But the problem here is it never finds the 1st product I add, so whenever I add that product again, it stacks the product every time and does not update the quantity of the product. Whereas for other products other than 1st, it acts as expected.

eg. when product A is added to empty cart, it adds itemid as A and qty = 1. When the product A is added again to an empty cart, it adds the itemid as A and qty=1 again (does not do qty=2). If I add B, C or others repeatedly it updates their qty as required

<?php
public function addinTable($id){
      $this->loadModel('Carts');

    /////////inserting into the cart table//////////7
      $item = $this->Products->get($id);
      $session = $this->request->session();

      $allProducts = $session->read('Cart');

    if(null!=$allProducts){
        echo "<br>if(allProducts is NOT EMPTY)<br>";
         if(array_search($id,array_column($allProducts, 'itemid'))){
            //if the id is already in list
                 echo "<br><b>ITEM Is IN the list already</b>";
            $key = array_search($id,array_column($allProducts, 'itemid'));
                echo "<br> key is ", $key;
            $newqty = debug($allProducts[$key]['qty']);
                echo "<br> new qty +1 = ".$newqty+=1;
                debug($allProducts[$key]['qty']++);
            $session->write('Cart',$allProducts);
               debug( $session->read('Cart'));
        }
        else{
          echo"<br><b>The id is not found but cart is not empty</b>";
            $allProducts[] = array('itemid'=>$id,
                                    'qty' => 1
                                  );
            debug( $session->read('Cart'));
        }

    }
     else{///////////if cart is empty at first
         echo"<br><b>The  cart is  empty</b>";
       $allProducts[] = array('itemid'=>$id,'qty' => 1);

          debug($allProducts[0]);
          debug($allProducts);
          debug($allProducts[0]['itemid']);

        //  if(array_search($id,array_column($allProducts, 'itemid'))==true){echo "hello";}
          $session->write('Cart',$allProducts);
                 debug($session->read('Cart'));
                     }
            $session->write('Cart',$allProducts);//save the item

  }
?>

Answer 1

array_search() returns the index, which is 0 for the first product. 0 evaluates to false.
You need a comparison against false here.

Change

if(array_search($id,array_column($allProducts, 'itemid'))) { //...

to

if(array_search($id,array_column($allProducts, 'itemid')) !== false) { //...

here's a fiddle that demonstrates this change: https://3v4l.org/m62Ya