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

You can define your custom function to calculate the sum of a list passed to it.

(defun sum (lst) (format t "The sum is ~s~%" (write-to-string (apply '+ lst))) 
EVAL: (sum '(1 4 6 4))
-> The sum is "15"