itertools

batched

# [
#     (0, 1, 2),
#     (3, 4, 5),
#     (6, ),
#     ...
# ]
for batch in itertools.batched(range(7), n=3):  # batch就是一个Tuple
    ...

chain('ABC', 'DEF') --> A B C D E F
chain(range(1, 6), range(4, 0, -1)) --> 1 2 3 4 5 4 3 2 1

# 和chain差不多， 但是只支持一个参数， 会对此展开后再用chain
def from_iterable(iterables):
    for it in iterables:
        for element in it:
            yield it

从某个数字开始一直循环

from itertools import count
loop = count(10)
next(loop) // 10
next(loop) // 11
next(loop) // 12
...

把一个迭代器变成多个独立的

for a, b in zip(iter1, iter2):  # 按照最短的来
    pass