您可以使用itertools.chain.from_iterable:
>>> from itertools import chain
>>> example_list = [['aaa'], ['fff', 'gg'], ['ff'], ['', 'gg']]
>>> '' in chain.from_iterable(example_list)
True
以防万一如果内部列表更大(超过 100 个项目),则使用any
使用生成器将比上面的示例更快,因为使用 Python for 循环的速度损失可以通过快速的补偿来补偿in
-手术:
>>> any('' in x for x in example_list)
True
时序比较:
>>> example_list = [['aaa']*1000, ['fff', 'gg']*1000, ['gg']*1000]*10000 + [['']*1000]
>>> %timeit '' in chain.from_iterable(example_list)
1 loops, best of 3: 706 ms per loop
>>> %timeit any('' in x for x in example_list)
1 loops, best of 3: 417 ms per loop
# With smaller inner lists for-loop makes `any()` version little slow
>>> example_list = [['aaa'], ['fff', 'gg'], ['gg', 'kk']]*10000 + [['']]
>>> %timeit '' in chain.from_iterable(example_list)
100 loops, best of 3: 2 ms per loop
>>> %timeit any('' in x for x in example_list)
100 loops, best of 3: 2.65 ms per loop