From: Frederic Chalons - Design Support IA Student <frederic.chalons@...>
Date: 2003-05-21T17:24:13+09:00
Subject: Copying an Array

Hi,

The = operator seems to retrieve an reference on a Array rather than 
copying what it contains
as in the following code:
*******
a = [1,2,3]
b = a

p b.id; p a.id
b.each_index do |i|
  b[i] *= 2
end
********
both a and b equals to [2,4,6]

This can be solve by using a.collect or a.dup but the problem would 
occur again if a,b are multi dimensions Array. dup or collect reference 
on the sub-Array?
Isn't there a clean and consise way to copy the whole content of an 
multi dimension Array so that the copy is not somehow linked to the 
original.

Btw, a would be modified even though it is accessed as attri_reader. So 
 I guess  =  is copying the pointer rather than any content (a.id == b.id)

(using ruby 1.6.8 (2002-12-24) [sparc-solaris2.8])

Thank you,
Fred