On 08/07/2013 01:50 AM, liuerfire Wang wrote: > Sorry for the title which didn't make clear. > > Here is a list x = [b, a, c] (a, b, c are elements of x. Each of them are different type). Now I wanna generate a new list as [b, > b, a, a, c, c]. If you don't care about the order, you can do: x = x + x