how to append to a list twice?

[Paul McGuire]

"John Salerno" <johnjsal at NOSPAMgmail.com> wrote in message
news:ui62g.1991$No6.43121 at news.tufts.edu...
> If I want to create a list of the form [100, 99, 99, 98, 98, 97, 97...]
> (where each item is repeated twice after the first one), how might I do
> that most efficiently?
>
> Right now I have this:
>
> series = [100]
> for x in range(10):   # just for testing
>      series.append(series[-1] - 1)
>
> But of course that only does it once, and I don't want to have to copy
> and paste the append line. Perhaps there's a better way than this.
>
> Thanks.

series = [100]
for x in range(10):   # just for testing
     series.extend([series[-1] - 1]*2)