From: Nikolay Pavlov <qpadla@...>
Date: 2007-09-12T02:57:17+09:00
Subject: alter_key function for Hash

Hallo all.
Of course i am reinventing the wheel, but may be that would be helpful for 
some one. With this method you can replace a key with a new one in a Hash.
It could be helpful for example if you want to parse a lot of XML documents 
in hash from various external sources in one Library, so that you can 
handle a unified interface.  

class Hash

  # Replace an old key with a new one
  #
  # === Arguments:
  # * old_key
  # * new_key
  def alter_key(old_key, new_key)
    raise IndexError.new("key already exist") if self[new_key]
    if self.has_key?(old_key)
      self[new_key] = self[old_key]
      self.delete(old_key)
    end
    return self
  end
end

irb(main):006:0> hash = Hash.new
=> {}
irb(main):007:0> hash[:old] = 10000
=> 10000
irb(main):008:0> hash.alter_key(:old, :new)
=> {:new=>10000}
irb(main):009:0> hash[:new]
=> 10000

-- 
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- Best regards, Nikolay Pavlov. <<<-----------------------------------    
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