From: walter a kehowski <wkehowski@...>
Date: 2005-08-08T07:36:08+09:00
Subject: Re: cartesian product

Hello,

The following is not in the spirit of previous comments

class Array

  def cartprod(b)

    c=[]
    each {|ae| b.each {|be| c << [ae, be] } }
    c.collect! {|ce| ce.flatten}

  end #cartprod

end #Array

a=[[1,2,3],[4,5,6],[7,8,9]]

c=a[0]
as=a.slice(1..a.length-1)
as.each {|ase| c=c.cartprod(ase) }
c.each  {|ce| ce.each {|x| print x," " }; print "\n" }

Would the following be desirable? If cartprod has two or more arguments, do 
the usual thing, but if it has just one, it takes the cartesian product with 
that argument, i.e, cartprod(a) gives cartprod(a,a) or a.cartprod(a), etc.

And thanks for all the suggestion so far. I usually just play around with 
Perl but got $#@% fatigue. It was a toss-up between Python and Ruby so here 
I am.

Walter Kehowski