From: Joel VanderWerf <vjoel@...>
Date: 2009-06-19T03:47:43+09:00
Subject: Re: Modifying data in an array using a reference

Ch Ba wrote:
>  Ok so my situation is as follows. I have an array "foo", which contains
> several instances of the class "bar". I get a copy of an object inside
> of "foo" using  foo.detect, and then modify that copy. Afterwards, I
> need to replace the original inside the array with the modified version.
> The problem is that I do not know the index of the object. How would I
> go about doing that? I could use some help =)

You're working with the original foo, not a copy, so you don't need to 
replace the entry at a certain index:

   class Bar
     attr_accessor :x
     def initialize x
       @x = x
     end
   end

   foo = [Bar.new(0), Bar.new(1)]
   p foo

   bar = foo.detect {|bar| bar.x > 0}
   bar.x = "changed"
   p foo

[#<Bar:0xb796c988 @x=0>, #<Bar:0xb796c974 @x=1>]
[#<Bar:0xb796c988 @x=0>, #<Bar:0xb796c974 @x="changed">]

-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407