Loop Backwards

[mensanator at aol.com]

Dave wrote:
> This should be simple, but I can't get it:
>
> How do you loop backwards through a list?
>
> For example, in, say, Javascript:
>
> for (var i  = list.length - 1; i >=0; i--) {
>     do_stuff()
> }
>
> I mean, I could reverse the list, but I don't want to. I want it to
> stay exactly the same, but I want to start at the end and end at the
> beginning.

Negative indexes start at the opposite end than positive indexes.

>>> s = [1,2,3,4,5]
>>> for i in range(len(s)):
	print s[-i-1],
	
5 4 3 2 1
>>> 


> 
> Thanks!
> 
> - Dave