# Extends the Array class with a function used to randomly choose elements.  Note that if you are using Rails, ActiveSupport recently was updated to include a similar
# function.  This code checks for the presence of that method and does not try to replace it.  They work the same though so no worries.
 
module ArrayRandomizer
  
  # Randomly chooses an element from an array
  # >> [1,2,3].rand = 3 
  # [].rand = nil

  def rand
    return self[Kernel.rand(self.size)]
  end

end

unless Array.respond_to?(:rand)
  Array.send :include, ArrayRandomizer
end