Re: How do i get multiple Min() values?

B. Pym wrote:

HenHanna wrote:
 

 
How do i get multiple Min() values?
 
          e.g.      for   Y = (x-2)*(x-3)   for x in range(-10,10)
                                   the min Y is hit twice
 
 
print(  min( ((x-2)*(x-3),  (x, (x-2, x-3)))
                                           for x in range(-10,10) ) )
 
 
 
is this easy in Scheme(Gauche) ?

 
Gauche Scheme
 
(use gauche.collection) ;; fold2
 
(define (min-by fn lst)
  (if (null? lst)
    (values '() #f)
    (fold2
      (lambda (x best worth)
        (let ((score (fn x)))
          (cond ((< score worth) (values (list x) score))
                ((= score worth) (values (cons x best) worth))
                (#t (values best worth)))))
      (take lst 1) (fn (car lst))
      (cdr lst))))
 
(min-by (lambda(x) (* (- x 2) (- x 3))) (lrange -10 11))
 
  ===>
(3 2)
0
 

(use gauche.collection) ;; fold2

(define (min-max-by fn lst)
  (define (use  compare x score best worth)
    (cond ((compare score worth) (list (list x) score))
          ((= score worth) (list (cons x best) worth))
          (#t (list best worth))))
  (if (null? lst)
    (values (list '() #f) (list '() #f))
    (let ((initial (list (take lst 1) (fn (car lst)))))
      (fold2
        (lambda (x mini maxi)
          (let ((score (fn x)))
            (values
              (apply use < x score mini)
              (apply use > x score maxi))))
        initial initial
        (cdr lst)))))

(min-max-by (lambda(x) (* (- x 2) (- x 3))) (lrange -10 11))

  ===>
((3 2) 0)
((-10) 156)