Illegal string offset only when iterated as a set

Question

I know there are many other questions on this but my case is quite peculiar, my illegal offset only occurs when I iterate it with the others but is fine when I do it on its own. I am using Slimframework. My array looks like this:

{
    "cart": {
        "cartId": "9c7b7c3e-d4d3-4de1-afa4-f81e63b50906",
        "orderNo": 1,
        "orderType": "Collection",
        "customerName": "",
        "customerTel": "",
        "address": "",
        "items": [
            {
                "itemId": 2,
                "itemName": "Item A",
                "itemPrice": 5.75,
                "qty": 1
            },
            {
                "itemId": 1,
                "itemName": "Item B",
                "itemPrice": 5.25,
                "qty": 1
            },
            {
                "itemId": 4,
                "itemName": "Item C",
                "itemPrice": 9.3,
                "qty": 1
            },
            {
                "itemId": 3,
                "itemName": "Item D",
                "itemPrice": 8.6,
                "qty": 1
            }
        ]
    },
    "shopId": 1,
    "discount": 0,
    "total": "28.90",
    "method": "Card"
}

When I do this in slimframework:

$order = $request->getParsedBody();
$this->response->withJson($order['cart']['items']);

It returns the exact same array moreover, if I check what is $order['cart']['items'][0]['itemPrice'] I get 5.75.

But when I iterate over it like:

foreach($order['cart']['items'] as $item)
        {
            $itemId = $item['itemId'];
            $item = $item['itemName'];
            $itemPrice = $item["itemPrice"];
            $itemQty = $item["qty"];
        }

I always get Illegal string offset 'itemPrice' & 'qty'.

I have also tried the below and it's not a problem:

$itemPrice;
foreach($order['cart']['items'] as $item)
        {
            $itemPrice .= $item["itemPrice"]
        }
$this->response->withJson($itemPrice);

I might be missing something really obvious, any pointers would be highly appreciated.

Answer 1

You did override your loops $item variable with $item['itemName'];. From this point on your $item variable has no "itemPrice" nor "qty" keys, because it is scalar. You just need to change variable namings.

foreach($order['cart']['items'] as $item)
        {
            $itemId = $item['itemId'];
            $item = $item['itemName']; /// <--- ! $item is no longer an item
            $itemPrice = $item["itemPrice"];
            $itemQty = $item["qty"];
        }