On Jun 9, 7:06 am, Ricardo Aráoz <[EMAIL PROTECTED]> wrote: > Mensanator wrote: > > On Jun 6, 1:40 pm, The Pythonista <[EMAIL PROTECTED]> wrote: > >> On Thu, 05 Jun 2008 23:42:07 -0400, John Salerno wrote: > >>> Is it possible to write a list comprehension for this so as to produce a > >>> list of two-item tuples? > >>> base_scores = range(8, 19) > >>> score_costs = [0, 1, 1, 1, 1, 1, 1, 2, 2, 3, 3] print zip(base_scores, > >>> score_costs) > >> score_costs = [(base_scores[i], score_costs[i]) for i in range (len > >> (base_scores))] > > > What happens if your iterables aren't the same length? > > >> But, I'd rather just use zip. :-) > > > And with zip() you won't get an error, but it won't be correct, > > either. > > Wouldn't it be nice to have leftZip(), rightZip(), and fullZip() for > when the lists have different lengths? The final tuples for a leftZip > could be in the form (value, ) and for right zip (, value) (though I > think this last tuple is not allowed in python's syntax, we might define > a "Null" or "Empty" name to act as a place holder in the resulting tuples).
You can go zip(xrange(9, 10000000000L), [0, 1, 1, 1, 1, 1, 1, 2, 2, 3, 3]) since xrange DOES NOT return a list but a constant-memory iterable. Also, there is itertools for adding default values after you fall off the end of a list. >>> import itertools >>> zip(xrange(100), itertools.chain([0, 1, 1, 1, 1, 1, 1, 2, 2, 3, 3], >>> itertools.cycle([None]))) Whose output is: [(0, 0), (1, 1), (2, 1), (3, 1), (4, 1), (5, 1), (6, 1), (7, 2), (8, 2), (9, 3), (10, 3), (11, None), (12, None), (13, None), (14, None), (15, None), (16, None), (17, None), (18, None), (19, None), (20, None), (21, None), (22, None), (23, None), (24, None), (25, None), (26, None), (27, None), (28, None), (29, None), (30, None), (31, None), (32, None), (33, None), (34, None), (35, None), (36, None), (37, None), (38, None), (39, None), (40, None), (41, None), (42, None), (43, None), (44, None), (45, None), (46, None), (47, None), (48, None), (49, None), (50, None), (51, None), (52, None), (53, None), (54, None), (55, None), (56, None), (57, None), (58, None), (59, None), (60, None), (61, None), (62, None), (63, None), (64, None), (65, None), (66, None), (67, None), (68, None), (69, None), (70, None), (71, None), (72, None), (73, None), (74, None), (75, None), (76, None), (77, None), (78, None), (79, None), (80, None), (81, None), (82, None), (83, None), (84, None), (85, None), (86, None), (87, None), (88, None), (89, None), (90, None), (91, None), (92, None), (93, None), (94, None), (95, None), (96, None), (97, None), (98, None), (99, None)] -- http://mail.python.org/mailman/listinfo/python-list
