Array#sample : I recently moved a project from ruby 1.9.1 to ruby 1.8.6, which doesn't have Array#sample. I couldn't find it online quickly, so I wrote one.

sample.rb

# Array#sample
# I recently moved a project from ruby 1.9.1 to ruby 1.8.6, which doesn't have
# Array#sample. I couldn't find it online quickly, so I wrote one.

class Array
  def sample(sample_size=1, acc=[])
    sample_size = self.size if acc.empty? && sample_size > self.size
    return acc if sample_size==0
    index_to_sample = (rand * self.size).floor
    if acc.include?(self[index_to_sample])
      sample(sample_size, acc)
    else
      sample( sample_size-1, acc<<self[index_to_sample] )
    end
  end
end