How to sum a list of numbers in Emacs Lisp?

Question

This works:

(+ 1 2 3)
6

This doesn\'t work:

(+ \'(1 2 3))

This works if \'cl-*\' is loaded:

Answer 1

This ought to do the trick:

(defun sum-list (list)
  (if list
      (+ (car list) (sum-list (cdr list)))
    0))

[source]

Edit: Here is another good link that explains car and cdr - basically they are functions that allow you to grab the first element of a list and retrieve a new list sans the first item.