def delete_row index
      idx = named_index_for index

      raise IndexError, "Index #{index} does not exist." unless @index.include? idx
      @index = Daru::Index.new(@index.to_a - [idx])
      each_vector do |vector|
        vector.delete_at idx
      end

      set_size
    end
def delete_row index
      idx = named_index_for index

      raise IndexError, "Index #{index} does not exist." unless @index.include? idx
      @index = Daru::Index.new(@index.to_a - [idx])
      each_vector do |vector|
        vector.delete_at idx
      end

      set_size
    end
Delete a row