Python过滤2个列表

Question

我正试图找到一种方法来使用一个列表来过滤掉另一个列表的元素。

有点像交叉语法但完全相反

lst = [0,1,2,6]

secondlst = [0,1,2,3,4,5,6]

预期结果

[3,4,5]

Answer 1

简单方法：

r = [v for v in secondlst if v not in lst]

或

list(set(secondlst).difference(lst))

Answer 2

只看Python的set()'类型。

>>> lst = [0,1,2,6]
>>> secondlst = [0,1,2,3,4,5,6]
>>> set(lst).symmetric_difference(set(secondlst))
set([3, 4, 5])

Answer 3

您可以使用filter

filter(lambda x: x not in lst, secondlst)

Answer 4

简单：

outcome = [x for x in secondlst if x not in lst]

如果lst很大，则更复杂但更快：

lstSet = set(lst)
outcome = [x for x in secondlst if x not in lstSet]