From Newsgroup: comp.lang.python
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
newLISP
(define (min-by fun lst)
(let (accum '() best 0 score 0)
(dolist (x lst)
(setf score (fun x))
(cond ((or (empty? accum) (< score best))
(setf best score)
(setf accum (list x)))
((= score best) (push x accum))))
(list accum best)))
(min-by (fn(n) (- (abs (* 10 n)))) '(0 9 2 2 -9 3))
===>
((-9 9) -90)
--- Synchronet 3.20a-Linux NewsLink 1.114