LISP: A dynamic car

I have a complex list of lists and want something to check the second element of every list of the list in the loop, any supported features like this?

>>18
That's quite imperative (the code style), also what's : and = supposed to do in your code, that part isn't valid Lisp syntax (unless there's a reader macro for : and = is bound to something or is a symbol macro).

What exactly is the function supposed to do, try giving some example inputs and outputs. Is it supposed to do the same as my get-arguments-of?