From: Jim Moy <web@...>
Date: 2003-12-13T07:05:58+09:00
Subject: [Nuby] Object ID Lookup?

Hi all, a Ruby Nuby here with a question.

Is there a way to lookup an object reference from the object's id? 
Something to do like the following, but without the need for the lookup
hash:

  a = { "a" => 1, "b" => 2 }
  b = { "c" => 4, "d" => 3 }
  arr = [a, b]
  ids = arr.collect {|h| h.id}
  lookup = {}
  arr.each { |h| lookup[h.id] = h }
  cmp = ids.collect {|id| lookup[id]}
  ids == cmp => true

In my instance, I've got a reference set of hashes that I'm pointing to
from multiple arrays.  Those arrays are manipulated depending on sorting
and other factors.

I don't want to get Hash#== involved so I'm using the Hash object id's. 
After processing is completed, I'd like to get back from the IDs to the
object references.  The lookup is working, but I was wondering if there
was a better method.

Thanks for any suggestions,

Jim Moy
Fort Collins, Colorado
USA