From: Stefano Crocco <stefano.crocco@...>
Date: 2008-12-28T20:02:36+09:00
Subject: Re: New to Ruby: copying arrays?

Alle Sunday 28 December 2008, John Park ha scritto:
> So here's my question.  Is there a simple and elegant way to duplicate
> the entire content of a multi-dimensional array?

You can use Marshal.dump and Marshal.load:

a = [["a", "b"],["c", "d"]]
b = Marshal.load(Marshal.dump(a))
a[0][0].upcase!
puts a[0][0]  #=> A
puts b[0][0]  #=> a

Note that this only works if your array only contains serializable objects (in 
particular, it should not contain method or proc objects, IO objects and 
singleton objects). See the documentation for the Marshal module for more 
information (using the command ri marshal).

>Oh, one more question: what's the difference between .dup and .clone
>methods?

As far as I know, the only difference is that clone also copies the frozen 
state of the original object, while dup doesn't:
s1 = "test"
s1.freeze
s2 = s1.dup
s3 = s1.clone
puts s2.frozen? #=> false
puts s3.frozen? #=> true

I hope this helps

Stefano