在zip和zip_longest之间是否有中间立场?
问题内容:
说我有以下三个列表:
a = [1, 2, 3, 4]
b = [5, 6, 7, 8, 9]
c = [10, 11, 12]
是否有内置函数,例如:
somezip(a, b) == [(1, 5), (2, 6), (3, 7), (4, 8)]
somezip(a, c) == [(1, 10), (2, 11), (3, 12), (4, None)]
行为介于zip
和之间zip_longest
?
问题答案:
没有,但是您可以轻松地将takewhile和izip_longest的功能结合起来以实现所需的功能
from itertools import takewhile, izip_longest
from operator import itemgetter
somezip = lambda *p: list(takewhile(itemgetter(0),izip_longest(*p)))
(如果第一迭代者的项目的评估结果为False,则可以使用lambda表达式替换itemgetter-请参阅@ovgolovin的注释)
somezip = lambda *p: list(takewhile(lambda e: not e[0] is None,izip_longest(*p)))
例子
>>> from itertools import takewhile, izip_longest
>>> from operator import itemgetter
>>> a = [1, 2, 3, 4]
>>> b = [5, 6, 7, 8, 9]
>>> c = [10, 11, 12]
>>> somezip(a,b)
[(1, 5), (2, 6), (3, 7), (4, 8)]
>>> somezip(a,c)
[(1, 10), (2, 11), (3, 12), (4, None)]
>>> somezip(b,c)
[(5, 10), (6, 11), (7, 12), (8, None), (9, None)]