(defun insert-n (n e lst / a b) (setq a lst) (repeat n (setq b (cons (car a) b) a (cdr a) ) ) (setq a (cons e a)) (foreach i b (setq a (cons i a)) ) a )
;;;移除第n项
(defun remove-n (n lst / a b) (setq a lst) (repeat n (setq b (cons (car a) b) a (cdr a) ) ) (setq a (cdr a)) (foreach i b (setq a (cons i a)) ) a )