How to efficiently proceed addition and subtraction in python list?

[Ant]

Tim Chase wrote:
> > I have a list AAA = [1, 2, 3] and would like to subtract one from list
> > AAA
> > so AAA' = [0, 1, 2]
> >
> > What should I do?
>
>
> Sounds like a list comprehension to me:

Also the built in function 'map' would work:

>>> a = [1,2,3]
>>> b = map(lambda x: x-1, a)
>>> b
[0, 1, 2]

List comprehensions are more pythonic, but map would probably be faster
if performance was a (real) issue.