[求助]如何取得一个序列里元素的总数?

vocabulary

各位前辈:
    如果有一个序列(setq a (list 15 28 33 26 17)),例如我不知道这个序列里一共有5个元素,我该如何取得这个序列的总元素个数?我又如何逐一来取得这个每个元素的值?下面是我设想的取值方法,请高手们帮我改一改好吗？先谢谢了!!!
(defun c:bl()
  (setq n (取得序列a的元素总数))
  (setq i 0)
  (repeat n
    (setq b (nth a i))
    (princ (strcat "\n " (itoa b))
    (setq i (1+ i))
  )
)

Andyhon

(defun c:bl()
  ;(setq n (取得序列a的元素总数))
   (setq n (length a))
  (setq i 0)
  (repeat n
    (setq b (nth i a))
    (princ (strcat "\n " (itoa b)))
    ;; or (terpri) (princ b)
    (setq i (1+ i))
  )
)

liu_kunlun

(defun c:bl()
  (setq n (length a))
  (setq i 0)
  (repeat n
    (setq b (nth i a ))
    (princ (strcat "\n " (itoa b))
    (setq i (+ i 1))
  )
)

vocabulary

谢谢楼上两位大侠,原来是(length)函数.

xyp1964

2. (defun c:test ()
3.   (setq a (list 15 28 33 26 17))
4.   (princ "\n总元素个数: ")
5.   (princ (length a))
6.   (princ "\n元素分别为: ")
7.   (foreach b a (princ "\n") (princ b))
8.   (princ)
9. )

(defun c:test ()   (setq a (list 15 28 33 26 17))   (princ "\n总元素个数: ")   (princ (length a))   (princ "\n元素分别为: ")   (foreach b a (princ "\n") (princ b))   (princ) )