From: Brian Adkins <lojicdotcom@...>
Date: 2008-11-06T02:38:24+09:00
Subject: Re: replace values in hash

Jason Lillywhite <jason.lillywhite@gmail.com> writes:

> how would I iterate over a hash, such as
>
> x = { 'a' => "hi", 'b' => nil, 'c' => "do"}
>
> and replace nil values with 'foo' then return the hash again?

~/temp$ cat -b temp.rb
     1	require 'pp'

     2	class Hash
     3	  def replace_value old, new
     4	    self.inject({}) do |result,pair| 
     5	      k, v = pair[0], pair[1]
     6	      result[k] = (v == old) ? new : v 
     7	      result
     8	    end 
     9	  end
    10	end

    11	x = { 'a' => "hi", 'b' => nil, 'c' => "do", :d => nil }
    12	pp x
    13	y = x.replace_value(nil, 'foo')
    14	pp y
~/temp$ ruby temp.rb
{"a"=>"hi", "b"=>nil, :d=>nil, "c"=>"do"}
{"a"=>"hi", "b"=>"foo", "c"=>"do", :d=>"foo"}

-- 
Brian Adkins
http://www.lojic.com/
http://lojic.com/blog/