def transpose
      Daru::DataFrame.new(
        each_vector.map(&:to_a).transpose,
        index: @vectors,
        order: @index,
        dtype: @dtype,
        name: @name
      )
    end
def transpose
      Daru::DataFrame.new(
        each_vector.map(&:to_a).transpose,
        index: @vectors,
        order: @index,
        dtype: @dtype,
        name: @name
      )
    end
Transpose a DataFrame, tranposing elements and row, column indexing.