From: Paul Harrington <xeno@...>
Date: 2010-09-25T11:58:52+09:00
Subject: Re: Using the same variable for an array and an iterator

Ryan wrote:
> I've just started learning Ruby and am going through a few tutorials.
> Right now I'm playing around with arrays and am getting a strange
> error.  I am creating an array named 'x' and creating an iterator
> named x as well.  Now I know that this isn't good practice but I'm
> getting a strange error.  The first time I iterate through the entire
> array, simply displaying the contents of the array, I don't get an
> error at all.  If I immediately run the iteration again I get a
> NoMethodError and am trying to figure out why.  Here's a screenshot
> http://bit.ly/bXZkjp
> Like I said, I know that this is bad practice, but I'm curious as to
> what is causing this error only after the first go through.

The error gives a hint as to what's happening. In Ruby 1.8, variables in 
a block clobber the variables of the outside scope. So your in your 
example, after each is finished iterating, "x" is now 4, even though x 
was defined within that block.

In Ruby 1.9 variables only exist within the scope they're declared in, 
so that doesn't have this problem.
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