From: Martin DeMello <martindemello@...>
Date: 2002-12-09T23:29:41+09:00
Subject: Re: multi-dimension array

Shannon Fang <xrfang@hotmail.com> wrote:
> Hi Guru,
>> >
>> > You're doing too much work -- let Ruby do it :-)
>> >
>> >   arr = (1..3).map { [0,0] }
>> >
> 
> That's really neat. Thanks for show us the ruby way.

Here's a quick extension to several dimensions, using Joel VanderWerf's
enum tools ( http://www.ruby-lang.org/raa/list.rhtml?id=657 )

require 'enum/tree'
require 'enum/op'

class << Array
  def n_dim(*args)
    return (1..args[0]).to_a.map! {nil} if args.length == 1
    a = args.shift
    (1..a).to_a.map! {n_dim(*args)}
  end
end

class Array  
  def deep_each
    self.by_depth { |x| x.kind_of?(Array) ? x : [] }.each {|i|
      yield i unless i.kind_of?(Array)
    }
  end
end

include EnumerableOperator
a = Array.n_dim(2,3,4)

product(0..1, 0..2, 0..3).each {|i,j,k| a[i][j][k] = "(#{i},#{j},#{k})" }

a.deep_each {|i| p i}