The map() Function can work simultaneously on more than one list.
These lists have to have the same length.
>>> a = [1,2,3,4]
>>> b = [17,12,11,10]
>>> c = [-1,-4,5,9]
>>> map(lambda x,y:x+y, a,b)
[18, 14, 14, 14]
>>> map(lambda x,y,z:x+y+z, a,b,c)
[17, 10, 19, 23]
>>> map(lambda x,y,z:x+y-z, a,b,c)
[19, 18, 9, 5]
About 12 years ago, Python aquired lambda, reduce(), filter() and map(), courtesy of (I believe) a Lisp hacker who missed them and submitted working patches. But, despite of the PR value, I think these features should be cut from Python 3000.
„So now reduce(). This is actually the one I've always hated most, because, apart from a few examples involving + or *, almost every time I see a reduce() call with a non-trivial function argument, I need to grab pen and paper to diagram what's actually being fed into that function before I understand what the reduce() is supposed to do. So in my mind, the applicability of reduce() is pretty much limited to associative operators, and in all other cases it's better to write out the accumulation loop explicitly.“
Quelle: http://www.artima.com/weblogs/viewpost.jsp?thread=98196