Python:从列表中删除项目直到项目符合条件的惯用方法？

Question

我刚写了这个小 helper ，但我有一种强烈的感觉，这种东西“早该存在”。它叫什么？

@listify
def drop_up_to_and_including(l, f):
    """Drops items from a list 'l' up until and including an element `e` is found for which `f(e) == True`

    Example::
    >>> drop_up_to_and_including(range(10), lambda x: x == 5)
    [6, 7, 8, 9]
    """
    found = False
    for e in l:
        if found:
            yield e

        if f(e):
            # note: after yield-statement; so we'll yield starting from the first item _after_ f(e) == True
            found = True

listify 做你想做的事:https://github.com/shazow/unstdlib.py/blob/master/unstdlib/standard/list_.py#L149

Answer 1

您可以使用 itertools.dropwhile但需要删除第一个匹配元素并且需要反转逻辑:

drop_up_to_and_including = lambda l,f : list(itertools.dropwhile(lambda y: not(f(y)),l))[1:]