From: Harry Ohlsen <harryo@...>
Date: 2001-05-27T11:10:05+09:00
Subject: [ruby-talk:15782] Subsets of a set

I know that the Array class has a number of methods that make it usable
for storing sets.

What I need is a method that will allow me to generate all of the
subsets of a given set
that are a certain size.

For example, if my set was { 1, 2, 3, 4 } then all the subsets of size 3
would be ...

   {1, 2, 3},  {1, 2, 4},  {2, 3, 4}

It will need to be a recursive routine.  I tried to write one, but only
got as far as having it
generate all sets of size 1 or the whole set.

Has anyone done this before?  If not, I'll just keep plugging away, but
I figure it never
hurts to ask!

TIA

Harry O.