在比较集合列表

Question

如何找到包含集合的两个列表的区别？

List 1:
    [{0, 1, 3, 9}, {2, 5, 6}, {8, 4}]
List 2:
    [{6, 7, 8, 9}]

结果应为：

[{7}]

Answer 1

创建两个集合并使用列表中的值填充它们。那么期望的结果就是简单的减法。

l1 = [{0, 1, 3, 9}, {2, 5, 6}, {8, 4}]
l2 = [{6, 7, 8, 9}]

s1 = set()
for i in l1:
    s1.update(i)

s2 = set()
for i in l2:
    s2.update(i)

print(s2 - s1)
# {7}

Answer 2

听起来你可以将list1弄平，然后找出差异：

>>> l1 = [{0, 1, 3, 9}, {2, 5, 6}, {8, 4}]
>>> l2 = [{6, 7, 8, 9}]
>>> l3 = [x for y in l1 for x in y]
>>> l3
[0, 9, 3, 1, 2, 5, 6, 8, 4]
>>> l4 = [set(i for i in l2[0] if i not in l3)]
>>> l4
[set([7])]