Gary Herron wrote: > >>> A = [1,2,3] > >>> B = [4,5,6] > >>> C = [7,8,9] > > >>> A+B+C > [1, 2, 3, 4, 5, 6, 7, 8, 9] > > >>> sum([A,B,C], []) > [1, 2, 3, 4, 5, 6, 7, 8, 9] Careful now, this can be very slow. sum uses __add__, not __iadd__, which gives this approach quadratic worst-case runtime. - Anders