How to get value from array? message: "Cannot use object of type stdClass as array"

That's easy.

PHP Code:

$details->production_companies[0]->id;

// Or

$a = ($details->production_companies);
$a[0]->id; 


before i use this code "$a[0]->id;" but message error.
but after I tried again it turned out to be. Surprisingly.

there might be an error when defining $a. hehe

Thanks