Python如何把两个列表相减呢？

Question

有1个有序日期列表A['2016-01-01','2016-01-02','2016-01-03',....'2017-06-01']
和1个无序的但是是需要排除的日期的列表B['2016-03-02','2016-03-08',]
希望把A中的包含的B元素全部去除掉，下面的写法可有不妥？

for x in B:
    A.remove(x)

Answer 1

A = [item for item in A if item not in set(B)]

Answer 2

a = ['2016-01-01','2016-01-02','2016-01-03','2017-06-01', '2016-03-08']
b = ['2016-03-02','2016-03-08',]
print set(a) - set(b)

Answer 3

看你需求吧,没啥毛病,数据也不是很多, 我提供一种方案

from collections import OrderedDict

d_set = OrderedDict.fromkeys(A)

for x in B:
    del d_set[x]

A = d_set.keys()

Answer 4

这种写法会报错,如果x 不在A 中就会报错,这种写法可以先加个 if 判断, x 是否在 A 中再执行 A.remove(x)

试试这个简单的写法:

#coding=utf-8
A = ['2016-01-01','2016-01-02','2016-01-03','2017-06-01','2017-06-01','2016-03-08','2016-03-08']
B = ['2016-03-02','2016-03-08']
C = []
for a in A:
    for b in B:
        if a == b:
            break
    else:
        C.append(a)
        
print C

Answer 5

from collections import OrderedDict
A = ['2016-01-01','2016-01-02','2016-01-03','2017-06-01','2016-03-08']
B = ['2016-03-02','2016-03-08']
d_set = OrderedDict.fromkeys(A)
for x in B:

if x in A:
    del d_set[x]

A = d_set.keys()