From: RichardOnRails <RichardDummyMailbox58407@...>
Date: 2008-09-07T10:19:03+09:00
Subject: Re: Need a 40 LOC (ignoring comments) to be shorter -- suggestions 	wanted

On Sep 5, 3:30 am, Lars Christensen <lar...@belunktum.dk> wrote:
> On Sep 5, 7:34 am, "Eric I." <rubytrain...@gmail.com> wrote:
>
> > On Sep 4, 9:40 pm, RichardOnRails
> > > Any ideas/suggestions?
>
> > Here's one solution that requires the 'permutation' gem:
>
> Ruby 1.8.7 and 1.9 has Array#permutation:
>
> (3..7).to_a.permutation.sort_by { |a| a[0..2].to_s.to_i *
> a[3..4].to_s.to_i }.first
>
> Golf anyone? :-)
>
> Lars

Hi Lars,

If this were the Olympics for succinct Ruby,  you’d get the Gold!!
Thanks for this expression.

> Ruby 1.8.7 and 1.9 has Array#permutation:

I’m running ruby 1.8.6, so of course “(3..7).to_a.permutation” failed

My work-around (which produced a correct result)  is:

a=[]; Permutation.new(5).each { |p| a << ((p.value.to_s.to_i +
3333).to_s)
=> 34567, 34576, 34657, 34675, 34756, 34765, 35467, [snip]
a.sort_by { |a| (a[0..2].to_s.to_i )*(a[3..4].to_s.to_i) }.first
=> 46735

Note that I compensated for the (3..7) ... construct not working  by
adding 33333 to each permutation.
Also,  I had to fix one blemish:  parentheses were needed around the
multiplicative factors;  a radix diagnostic was issued without them..
Maybe it’s another 1.8.6 problem

Again, thanks for this neat construct.  I’m going to introduce to my
granddaughter as a first step of a programmed solution to the problem
she presented.  But then,  I’ll admit it takes a Ruby pro to achieve
that level of brevity.  I’ll follow that with my more mundane approach
and see whether she’ll hang in there until achieving a glimmer of
insight into Ruby programming.

If you have any more enlightenment on these issues, I’d be pleased to
receive them.

Best wishes,
Richard