This works:
(+ 1 2 3)
6
This doesn\'t work:
(+ \'(1 2 3))
This works if \'cl-*
\' is loaded:
Linearly recursive function (sum L)
;;
;; sum
;;
(defun sum(list)
(if (null list)
0
(+
(first list)
(sum (rest list))
)
)
)
If you manipulate lists and write functional code in Emacs, install dash.el library. Then you could use its -sum function:
(-sum '(1 2 3 4 5)) ; => 15
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.
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"
(insert (number-to-string (apply '+ '(1 2 3))))
(apply '+ '(1 2 3))