How do i get multiple Min() values?

[HenHanna]

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) ?

[HenHanna]

Post by HenHanna
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) ?

if the Min() is going to check all of the Candidate values,
it could (at least) tell us how many times the Min value was seen!

[Kaz Kylheku]

Post by HenHanna

Post by HenHanna
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) ?

if the Min() is going to check all of the Candidate values,
it could (at least) tell us how many times the Min value was seen!

I decided to add something like this to TXR Lisp.

It will appear in 296.

This is the TXR Lisp interactive listener of TXR 295.
Quit with :quit or Ctrl-D on an empty line. Ctrl-X ? for cheatsheet.
When transferring between containers, do not siphon TXR by mouth.
1> (find-mins -10..11 : [callf * pppred ppred])
(2 3)
2> (find-mins (vec-seq -10..11) : [callf * pppred ppred])
#(2 3)
3> (find-mins "abracadabra")
"aaaaa"
4> (find-maxes "abracacabra")
"rr"

I works with any less-like function, assuming equality
when it’s neither true that x is less than y, nor that
y is less than x.

[B. Pym]

Post by HenHanna
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

[HenHanna]

Post by B. Pym

Post by HenHanna
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

Thank you... i think Python and Scheme(Gauche) should give
me this by default:

a list(collection) of all the
( key1 "data1" ... etc )
( key2 "data2" ... etc ) ...

for which the Min key value was seen.

[B. Pym]

Post by B. Pym

Post by HenHanna
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)

[B. Pym]

Post by B. Pym

Post by HenHanna
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)