From: "Shot (Piotr Szotkowski)" <shot@...>
Date: 2007-12-17T00:03:11+09:00
Subject: Re: An idiomatic way to traverse all pairs in an enumerable?

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MonkeeSage:

> module Enumerable
>   def every_pair(other)
>     self.each { | x |
>       other.each { | y |
>         yield [x, y] if x < y
>       }
>     }
>   end
> end

Ah, perfect. In my (limited) case, it ended up to be

module Enumerable
  def every_pair
    each_with_index do |a, i|
      each_with_index do |b, j|
        yield [a, b] if i < j
      end
    end
  end
end

>> arr =3D (1..5).sort_by { rand }
=3D> [1, 4, 2, 5, 3]
>> arr.every_pair { |a, b| p [a, b] }
[1, 4]
[1, 2]
[1, 5]
[1, 3]
[4, 2]
[4, 5]
[4, 3]
[2, 5]
[2, 3]
[5, 3]
=3D> [1, 4, 2, 5, 3]

Most appreciated!

-- Shot
--=20
XML is like violence, if it doesn't solve
your problem you're not using enough of it.

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