From: Austin Ziegler <austin@...>
Date: 2003-11-19T16:02:34+09:00
Subject: Re: Multi-dimensioned sparse array ?

On Wed, 19 Nov 2003 14:21:19 +0900, Charles Hixson wrote:
> Does anyone have an implementation of a multi-dimensioned sparse
> array?

What about using hashes?

  msa = Hash.new { |h, k| h[k] = Hash.new }

If you just use Numeric keys, there's little difference for your
needs. You can subclass Hash to make it act a bit more like an Array
under certain circumstances (e.g., #each would return values in
key-order instead of a key-value pair; you could also do an ordered
hash per [ruby-talk:20551] to potentially save sort times).

For multi-dimensional auto-vivifying, you could do:

  hash_maker = proc { |h, k| h[k] = Hash.new(&hash_maker) }
  msa = Hash.new(&hash_maker)

http://www.rubygarden.org/ruby?HashOfHashes

-austin
--
austin ziegler    * austin@halostatue.ca * Toronto, ON, Canada
software designer * pragmatic programmer * 2003.11.19
                                         * 01.34.12