如何从Python3中的生成器列表中采样?

使用 chain.from_iterable 具有 zip

>>> cc = chain.from_iterable(zip(*gen_list))
>>> next(cc)
1
>>> next(cc)
2
>>> next(cc)
3
>>> next(cc)
1
>>> next(cc)
2
>>> next(cc)
3

itertools recipes .

如果生成器的长度都相同(包括无限长),则可以 chain together zip() :

from itertools import chain

chain.from_iterable(zip(*gen_list))

roundrobin() example from the itertools documentation :

from itertools import cycle, islice

def roundrobin(*iterables):
    "roundrobin('ABC', 'D', 'EF') --> A D E B F C"
    # Recipe credited to George Sakkis
    num_active = len(iterables)
    nexts = cycle(iter(it).__next__ for it in iterables)
    while num_active:
        try:
            for next in nexts:
                yield next()
        except StopIteration:
            # Remove the iterator we just exhausted from the cycle.
            num_active -= 1
            nexts = cycle(islice(nexts, num_active))

后者的演示:

>>> from itertools import repeat, islice
>>> ones_gen = repeat(1)
>>> twos_gen = repeat(2)
>>> limited_threes_gen = islice(repeat(3), 2)  # just two values
>>> rrgen = roundrobin(ones_gen, twos_gen, limited_threes_gen)
>>> next(rrgen)
1
>>> next(rrgen)
2
>>> next(rrgen)
3
>>> next(rrgen)
1
>>> next(rrgen)
2
>>> next(rrgen)
3
>>> next(rrgen)
1
>>> next(rrgen)
2
>>> next(rrgen)
1

3号发电机用完了,但另外两台发电机还在继续运转。