打印数字列表中最长的数字序列（python）

Question

我有一个数字列表：

a=[2,3,4,5,1,3,2,4,5,6,2,6,7,5,2,7,5,6,2]

我想要最长的不包含2的序列，所以答案是：

[3,4,5,1,3]

我怎么能在python中这样做？ 谢谢你的帮助，

Answer 1

您可以使用itertools.groupby()：

from itertools import groupby

a = [2, 3, 4, 5, 1, 3, 2, 4, 5, 6, 2, 6, 7, 5, 2, 7, 5, 6, 2]

# get the subsequences not containing 2
subsequences = (list(it) 
                for contains_two, it in groupby(a, lambda x: x == 2)
                if not contains_two)

# find the longest one among them
print(max(subsequences, key=len))

打印

[3, 4, 5, 1, 3]