util.py 文件源码

def partition(pred, iterable):
    """Use a predicate to partition entries into false entries and true entries."""
    # https://stackoverflow.com/questions/8793772/how-to-split-a-sequence-according-to-a-predicate
    # NOTE: this might iterate over the collection twice
    # NOTE: need to use filter(s) here because we're lazily dealing with iterators
    it1, it2 = itertools.tee(iterable)
    return itertools.filterfalse(pred, it1), filter(pred, it2)  # pylint: disable=bad-builtin