구성표의 목록에 그룹 번호가 있습니까?

Question

목록이 주어지면 같은 요소를 그룹화하는 목록으로 목록을 분할해야합니다.

예

: 수 ((37 37) (39 39) (38 38 38) (40 40))

'(37 37 39 38 38 39 38 40 40 38)에 발생하는' 누구든지 이걸 도와 줘?

Answer 1

여기를 수행하는 한 방법이다 :

(define (group lst) 
    (let iter ((lst lst) (found null) (res null)) 
    (if (null? lst) ; all done ... 
     (reverse res) ; ... return result (reversed) 
     (let ((c (car lst))) ; isolate first element 
      (if (member c found) ; already processed that 
       (iter (cdr lst) found res) ; just go on with the next 
       (iter (cdr lst) ; otherwise add this to found and create a list of as many elements ... 
        (cons c found) ; ... as found in the list to the current result ... 
        (cons (make-list (count (curry equal? c) lst) c) res))))))) ; ... and go on with the next 

테스팅

> (group '(37 37 39 38 38 39 38 40 40 37)) 
'((37 37 37) (39 39) (38 38 38) (40 40)) 
> (group '(37 37 39 38 38 39 38 40 40 38)) 
'((37 37) (39 39) (38 38 38 38) (40 40))