Elisp: List, Get Elements

By Xah Lee. Date: 2023-06-22. Last updated: 2024-05-26.

The following are basic functions to get elements from a list.

Get Nth Item

nth

(nth n list)

nth element. (Index starts from 0.)

(nth 0 (list 2 3 4))
;; 2

car

(car list)

first element

(car (list "a" "b" "c"))
;; "a"

cdr

(cdr list)

rest elements

(cdr (list 0 1 2 3 4))
;; (1 2 3 4)

nthcdr

(nthcdr n list)

rest starting at n.

(nthcdr 2 (list 0 1 2 3 4))
;; (2 3 4)

butlast

(butlast list n)

drop the last n elements.

(butlast (list 0 1 2 3 4 5))
;; (0 1 2 3 4)

(butlast (list 0 1 2 3 4 5) 1)
;; (0 1 2 3 4)

(butlast (list 0 1 2 3 4 5) 2)
;; (0 1 2 3)

last

(last list &optional n)

🛑 WARNING: when n is 1, it still return a list. To get the actual last item, use car on result.

(last (list 0 1 2 3 4) 2)
;; (3 4)

;; return a list with just the last item
(last (list 3 4 5))
;; (5)

;; get the actual last item
(car (last (list 3 4 5)))
;; 5