getting data from array attribute

if you have only single object inside array then you can use this

$arr = array:1 [▼
            0 => {#533 ▼
                "BOOKID": "1"
                "REMAINING": 17.0
            }
        ]

$object = collect($arr);
$item = $object->first();
dd($item->REMAINING);

But if you have multiple objects inside array then use this

$arr = array:1 [▼
            0 => {#533 ▼
                "BOOKID": "1"
                "REMAINING": 17.0
            },
            1 => {#533 ▼
                "BOOKID": "1"
                "REMAINING": 17.0
            }
        ]
$object = collect($arr);
$list = $object->pluck("REMAINING");
dd($list);

By using above example you will get list of all the Remainings from array object.

Hope this will help you.

Array numeration starts with 0 so $array[0] is the first element, not $array[1].

$stockBook = (array)$stockBook;
$remain_ = $stockBook[0]['REMAINING'];

Try this:

$stockBook[0]->REMAINING;

If you want to retrieve element from array use []

If you want to retrieve element from object use ->

In your example we see that you have array of php objects, then you should use both.

    foreach((array)$stockBook as $key => $value){  // $stockBook or $stockBook[0]
        var_dump($key, $value);
    }
    // or
    var_dump($stockBook->BOOKID, $stockBook->REMAINING); // $stockBook or $stockBook[0]

If this is your data structure

array:1 [▼
  0 => {#533 ▼
    +"BOOKID": "1"
    +"REMAINING": 17.0
  }
]

and this is what you do

$remain_ = $stockBook[1]['REMAINING'];
    Undefined offset: 1

Then the error message explain the first part of your problem. You are trying to access the element with index 1 in an array that only has one element with index 0. Arrays are zero-based. That means, the first element is 0, the second is 1 etc. So you are trying to access an element that doesn't exist.

The second issue, according to your comment

Cannot use object of type stdClass as array when I did $remain_ = $stockBook[0]['REMAINING'];

indicates that each element in the array is an object. So to get the REMAINING attribute of the object at index 0 in the array you could do.

echo $stockBook[0]->REMAINING; // would print "17.0"