From: Aldric Giacomoni <aldric@...>
Date: 2009-12-18T02:29:49+09:00
Subject: Re: Unique combination of values from arrays

Milo Thurston wrote:
> 
> The purpose is so that I can find all the unique combinations of 
> parameters for different fields in SQL queries for some data I have.

Well, I shamelessly stole and adapted the code from there:
http://stackoverflow.com/questions/710670/c-permutation-of-an-array-of-arraylists

def array_permutations index, array
  result = []
  if index == array.size
    result << ""
    return result
  end
  array[index].each do |element|
    array_permutations(index + 1, array).each do |x|
      result << "#{element}, #{x}"
    end
  end
  return result
end

It's a bit ugly, but it'll pretty much do what you want. Let me know if 
you can come up with a better variable name than 'x' ;-)

irb(main):051:0> one = ['one', 'two']
=> ["one", "two"]
irb(main):052:0> two = ['three', 'four']
=> ["three", "four"]
irb(main):053:0> three = ['five', 'six']
=> ["five", "six"]
irb(main):054:0> a = array_permutations 0, [one, two, three]
=> ["one, three, five, ", "one, three, six, ", "one, four, five, ", 
"one, four, six, ", "two, three, five, ",
"two, three, six, ", "two, four, five, ", "two, four, six, "]
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