使用 yield from 展开嵌套的列表

def flatten(items, ignore_types=(str, bytes)):
    for x in items:
        if isinstance(x, Iterable) and not isinstance(x, ignore_types):
            yield from flatten(x)
        else:
            yield x
items = [1, 2, [3, 4, [5, 6], 7], 8]
for x in flatten(items):
    print(x, end='')

>>> 12345678