1 # coding=utf-8 2 a = [1, 2] 3 b = [2, 3, 4] 4 5 s1 = set(a) 6 s2 = set(b) 7 8 ret1 = s1.difference(s2) 9 ret2 = s1.symmetric_difference(s2) 10 11 print(ret1) 12 print(ret2)
输出结果：
1 {1} 2 {1, 3, 4}
结论：
difference 是拿自己跟别人做比较得到一个返回结果
symmetric_difference 是自己跟别人做比较，然后别人也跟你做比较，把两者之间没有的返回给一个值。