使用PHP SDK从Paypal获取SKU值

I'm using the Paypal PHP SDK.

I can get this value:

$mail = $payment->payer->payer_info->email;
$name = $payment->payer->payer_info->first_name;
$lname = $payment->payer->payer_info->last_name;
$contry = $payment->payer->payer_info->shipping_address->country_code;

But, I wasn't able to get SKU. I tried these options:

// Option #1
$sku =  $payment->transactions->item_list->items->sku;

// Option #2
$sku =  $payment->transactions->item_list->items->0->sku;

But get nothing, and an error for the second option.

some part of output:

....
"payer": {
    "payment_method": "paypal",
    "status": "VERIFIED",
    "payer_info": {
        "email": "mymail@gmail.com",
        "first_name": "name",
        "last_name": "mylastname",
        "payer_id": "00000000",
        "shipping_address": {
            .....
        },
        "country_code": "nnnnn",
        "business_name": "nnnnn"
    }
},
"transactions": [
    {
        "amount": {
            "total": "0.01",
            "currency": "USD",
            "details": {}
        },
        "payee": {
            "merchant_id": "00000000000",
            "email": "mymail@gmail.com"
        },
        "description": "Payment description",
        "invoice_number": "000000000",
        "item_list": {
            "items": [
                {
                    "name": "nnnnnn",
                    "sku": "1562",
                    "price": "0.01",
                    "currency": "USD",
                    "quantity": 1
                }
            ],
            ....

How can I get the value of SKU (1562)?

Try this:-

 $sku = $payment['transactions']['item_list']['items']['sku'];

i find some good code here : https://www.formget.com/paypal-transaction-details/

it must be like :

transactions[0]->item_list->items[0]->price ;

transactions & items are array like Gabor said .