beginner wrote: > How do I map a list to two lists with list comprehension? > > For example, if I have x=[ [1,2], [3,4] ] > > What I want is a new list of list that has four sub-lists: > > [[1,2], [f(1), f(2)], [3,4], [f(3), f(4)]] > > [1,2] is mapped to [1,2] and [f(1), f(2)] and [3,4] is mapped to > [3,4], [f(3), f(4)]. > > I just can't find any way to do that with list comprension.
>>> [a for b in ((item, map(f, item)) for item in x) for a in b] [[1, 2], [f(1), f(2)], [3, 4], [f(3), f(4)]] > I ended up > using a loop (untested code based on real code): > > l=[] > for y in x: > l.append(y) > l.append([f(z) for z in y]) Using a loop gives you clearer code in this case, so I'd use that. Peter -- http://mail.python.org/mailman/listinfo/python-list
