RubyのMatrixの拡張 []= と to_s

gistfile1.rb

class Matrix
  # m[i,j] = x
  def []=(i,j,x)
    @rows[i][j]=x
  end

  # m.to_s
  def to_s(separator = ", ")
    str = ''
    self.row_size.times do |i|
      str << self.row(i).to_a.join("#{separator}") + "\n"
    end
    return str
  end
end