P03 - Find the K'th element of a list

lisp

;;; Function that returns the element in the K-th position of ;;;
;;; a list. If the desired position is greater than ;;;
;;; last of the list, returns NIL.                       ;;

(defun element-at (org-list pos &optional (ini 1))
    (if (eql ini pos)
        (car org-list)
        (element-at (cdr org-list) pos (+ ini 1)))

;;; Other solution

(defun element-at (list n)
  (if (= n 1)
      ;; the first element is in position 1
      (first list)
    (element-at (rest list) (1-n))
    )
  )