~fumi/ChangeLog

ruby-list 39588 からのスレッドより

Simple に

class Array
  def randomize
    sort_by{ rand(100) }
  end

  def randomize!
    replace randomize
  end
end

速度を気にする場合

class Array
  def randomize!
    length.times do |i1|
      i2 = rand(length)
      t = self[i1]
      self[i1] = self[i2]
      self[i2] = t
    end
  end

  def randomize
    result = self.dup
    result.randomize!
    result
  end
end

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