I have used this code to print the data in the cart parameter

echo "<pre>";
            $cartData = $this->getRequest()->getParam('cart');
            print_r($cartData);

the output is like this in the nested array, the inner array does not contain data it contains a string

Array
(
    [504102] => Array
)

Expected output:

Array 
(
      [2283] => Array  
                ( 
                  [qty] => 2 
                ) 
)