php access object keys/values

Question

I was wondering how I could go about accessing values within an object, such as 'backpackPosition'? I'm guessing I would have to put it in some kind of foreach loop, but I have no idea how to get the values.

TF2Inventory Object
(
[fetchDate] => 1234541231
[items] => Array
(
    [60] => TF2Item Object
        (
            [equipped] => Array
                (
                    [scout] => 1
                    [sniper] => 1
                    [soldier] => 1
                    [demoman] => 1
                    [medic] => 1
                    [heavy] => 1
                    [pyro] => 1
                    [spy] => 1
                )

            [attributes] => Array
                (
                    [0] => stdClass Object
                        (
                            [name] => custom employee number
                            [class] => set_employee_number
                            [value] => 0
                        )

                    [1] => stdClass Object
                        (
                            [name] => cannot trade
                            [class] => cannot_trade
                            [value] => 1
                        )

                )

            [backpackPosition] => 61
            [className] => tf_wearable
            [count] => 1
            [defindex] => 170
            [id] => 535518002
            [level] => 20
            [name] => Primeval Warrior
            [quality] => unique
            [slot] => misc
            [tradeable] => 
            [type] => Badge
        )

    [43] => TF2Item Object
        (
            [equipped] => Array
                (
                    [scout] => 0
                    [sniper] => 0
                    [soldier] => 0
                    [demoman] => 0
                    [medic] => 0
                    [heavy] => 0
                    [pyro] => 0
                    [spy] => 0
                )

            [attributes] => Array
                (
                    [0] => stdClass Object
                        (
                            [name] => cannot trade
                            [class] => cannot_trade
                            [value] => 1
                        )

                )

            [backpackPosition] => 44
            [className] => tf_wearable
            [count] => 1
            [defindex] => 471
            [id] => 535518003
            [level] => 50
            [name] => Proof of Purchase
            [quality] => unique
            [slot] => head
            [tradeable] => 
            [type] => Hat
        )

    [42] => TF2Item Object
        (
            [equipped] => Array
                (
                    [scout] => 1
                    [sniper] => 1
                    [soldier] => 1
                    [demoman] => 1
                    [medic] => 1
                    [heavy] => 1
                    [pyro] => 1
                    [spy] => 1
                )

            [attributes] => 
            [backpackPosition] => 43
            [className] => tf_wearable
            [count] => 1
            [defindex] => 278
            [id] => 541628464
            [level] => 31
            [name] => Horseless Headless Horsemann's Head
            [quality] => unique
            [slot] => head
            [tradeable] => 
            [type] => Hat
        )

    [59] => TF2Item Object
        (
            [equipped] => Array
                (
                    [scout] => 0
                    [sniper] => 0
                    [soldier] => 0
                    [demoman] => 0
                    [medic] => 0
                    [heavy] => 0
                    [pyro] => 0
                    [spy] => 0
                )

            [attributes] => Array
                (
                    [0] => stdClass Object
                        (
                            [name] => cannot trade
                            [class] => cannot_trade
                            [value] => 1
                        )

                )

            [backpackPosition] => 60
            [className] => tf_wearable
            [count] => 1
            [defindex] => 115
            [id] => 548155039
            [level] => 10
            [name] => Mildly Disturbing Halloween Mask
            [quality] => unique
            [slot] => head
            [tradeable] => 
            [type] => Holiday Hat
        )

Answer 1

foreach($inventory_object->items as $item)
{
    $item->backpackPosition;
}