From: Trans <transfire@...>
Date: 2008-11-05T16:39:48+09:00
Subject: Re: replace values in hash

On Nov 5, 1:53 am, Jason Lillywhite <jason.lillywh...@gmail.com>
wrote:
> how would I iterate over a hash, such as
>
> x = { 'a' => "hi", 'b' => nil, 'c' => "do"}

  x.each{ |k,v| x[k] = 'foo' unless v }

However, it is not always sane to alter something while you are
iterating over it. So,

  h = {}
  x.each{ |k,v| h[k] = v.nil? ? v : 'foo' }
  x.replace(h)

Or use Facets Enumerable#mash (alias #graph)

  require 'facets/enumerable/mash'

  x = x.mash{ |k,v| [k, v.nil? ? v : 'foo'] }

http://facets.rubyforge.org/doc/api/core/classes/Enumerable.html#M000429

7.