Convert 2-item list to a dotted pair?

Question

Q: how can I convert a 2-item list to a dotted pair cons cell?

I can convert a 2-item list to a dotted pair with:

(let ((list '(1 2)))
  (cons (car list) (cadr list)))        ; => (1 . 2)

I'm blanking: is there a built-in function that does this, or should I roll my own?

Answer 1

cons makes a cons cell out of two arguments. apply uses a list as arguments to a function. When their powers combine: (apply #'cons x) converts a two element list into a cons cell (without having to poke around inside the list) and raises an error if the list isn't 2 long.