From: Daniel Finnie <danfinnie@...>
Date: 2008-01-08T02:53:37+09:00
Subject: Re: compact or uniq that takes a block like sort?

A more general solution:

require 'set'

class Array
 def uniq(&blk)
   blk ||= lambda {|x| x}
   already_seen = Set.new
   uniq_array = []

   self.each_with_index do |value, i|
     x = blk.call(value)
     unless already_seen.include? x
       already_seen << x
       uniq_array << value
     end
   end
   uniq_array
 end
end

and

 class Array
  def consolidate
    reverse.uniq {|a| a.first}.reverse
  end
 end

Of course, the value that you keep for uniq is kinda arbitrary.

Dan
- Hide quoted text -

On 1/7/08, Joel VanderWerf <vjoel@path.berkeley.edu> wrote:
> Pit Capitain wrote:
> > 2008/1/7, Bil Kleb <Bil.Kleb@nasa.gov>:
> >> I'm looking for an elegant way to do the following:
> >> (...)
> >
> > Bil, this makes the test pass:
> >
> >   class Array
> >     def consolidate
> >       Hash[*flatten].sort
> >     end
> >   end
>
> That certainly is elegant!
>
> Maybe Bil wanted to preserve the monotonicity?
>
>    class Array
>      def consolidate
>        Hash[*flatten].sort_by {|x,y| y}
>      end
>    end
>
>    p [ [5,1] , [3,2] ].consolidate # ==> [[5, 1], [3, 2]]
>
> --
>        vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407
>
>