zip_test.py

In [37]: a = iter(range(45))

In [38]: zip(*[a, a, a])
Out[38]:
[(0, 1, 2),
 (3, 4, 5),
 (6, 7, 8),
 (9, 10, 11),
 (12, 13, 14),
 (15, 16, 17),
 (18, 19, 20),
 (21, 22, 23),
 (24, 25, 26),
 (27, 28, 29),
 (30, 31, 32),
 (33, 34, 35),
 (36, 37, 38),
 (39, 40, 41),
 (42, 43, 44)]

In [39]: zip(*[iter(mylist), iter(mylist), iter(mylist)])
Out[39]:
[(0, 0, 0),
 (1, 1, 1),
 (2, 2, 2),
 (3, 3, 3),
 (4, 4, 4),
 (5, 5, 5),
 (6, 6, 6),
 (7, 7, 7),
 (8, 8, 8),
 (9, 9, 9),
 (10, 10, 10),
 (11, 11, 11),
 (12, 12, 12),
 (13, 13, 13),
 (14, 14, 14),
 (15, 15, 15),
 (16, 16, 16),
 (17, 17, 17),
 (18, 18, 18),
 (19, 19, 19),
 (20, 20, 20),
 (21, 21, 21),
 (22, 22, 22),
 (23, 23, 23),
 (24, 24, 24),
 (25, 25, 25),
 (26, 26, 26),
 (27, 27, 27),
 (28, 28, 28),
 (29, 29, 29),
 (30, 30, 30),
 (31, 31, 31),
 (32, 32, 32),
 (33, 33, 33),
 (34, 34, 34),
 (35, 35, 35),
 (36, 36, 36),
 (37, 37, 37),
 (38, 38, 38),
 (39, 39, 39),
 (40, 40, 40),
 (41, 41, 41),
 (42, 42, 42),
 (43, 43, 43),
 (44, 44, 44)]
 
# reference 的概念
# [iter(mylist)] * 5 是 5 個 iter(mylist) 的 ref，指向同一個 iter instance
# [iter, iter, ...] 是 5 個 iter 的 reference 指向 5 個 iter instance