[编程交流] LISP测试元素是否为

(setq ItemCounter 0)                            ;occurrencies counter set to 0
(while (member theItem theList)                 ;test if item belong to list
(setq theList (cdr (member theItem theList))   ;if found retain list after occurrence
      ItemCounter (1+ ItemCounter))            ; and index the counter
)

(defun AT:ListDuplicates (lst)
 ;; Return all duplicates within list
 ;; lst - List to process
 ;; Alan J. Thompson, 11.01.09
 (vl-remove-if-not (function (lambda (x) (member x (cdr (member x lst))))) lst)
)

(at:listduplicates '(1 2 3 4 5 1 2 3)) -> [color=Red](1 2 3 1 2 3)[/color]

(defun count_occurs (lst)
 (if (car lst)
   (cons (cons (car lst)
 (length (vl-remove-if-not
    (function (lambda (x)
         (eq x (car lst))))
    lst))
 )
  (count_occurs
    (vl-remove-if
      (function (lambda (x)
    (eq x (car lst))))
      lst)
    )
  )
   )
 )

(defun _ListDuplicateCount (lst / c new)
 ;; Alan J. Thompson, 06.25.10
 (foreach x (vl-remove-if-not (function (lambda (x) (member x (cdr (member x lst))))) lst)
   (if (setq c (assoc x new))
     (setq new (subst (cons x (+ (cdr c) 1)) c new))
     (setq new (append new (list (cons x 1))))
   )
 )
)

(defun mip_MakeUniqueMembersOfListWithCount  ( lst / OutList head countelt)
;; ===== mip_MakeUniqueMembersOfListWithCount =====
;; Removes the same (duplicate) items from the list
;; Quantifying the number of occurrences of an element
;; Use:
;; (Mip_MakeUniqueMembersOfListWithCount '(1 2 3 1 2 3 1 1 2 2))
;; Return ((1. 4) (2. 4) (3. 2))  
 (while lst
   (setq head (car lst)
  countelt 0
         lst (vl-remove-if '(lambda(pt)(if (equal pt head 1e-6)(setq countelt (1+ countelt)) nil)) lst)
         OutList (append OutList (list (cons head countelt)))))
 OutList
 )

(defun _ListDuplicateCounter (lst / c new)
 ;; Alan J. Thompson, 06.26.10
 (foreach x lst
   (if (setq c (assoc x new))
     (setq new (subst (cons x (1+ (cdr c))) c new))
     (setq new (append new (list (cons x 1))))
   )
 )
)