# File lib/mega/harray.rb, line 60
  def &(ha)
    nha=HArray.new
    (0..self.length-1).each do |i|
      if ha.has_value?(self.fetch(i)) and !nha.has_value?(self.fetch(i))
        nha.set(nha.length,self.fetch(i))
      end
    end
    nha
  end