NSMutableArray *arr1 = [[NSMutableArray alloc] initWithObjects:@"1",@"2",@"3",@"4",@"5", nil];
NSMutableArray *arr2 = [[NSMutableArray alloc] initWithObjects:@"1",@"2",@"3", nil];
NSMutableSet *set1 = [NSMutableSet setWithArray:arr1];
NSMutableSet *set2 = [NSMutableSet setWithArray:arr2];
// 取差集
[set1 minusSet:set2];
NSLog(@"差集:%@",set1.allObjects); // 差集的结果为:4,5
// 取并集
[set1 unionSet:set2];
NSLog(@"并集:%@",set1.allObjects); // 并集的结果为:1,2,3,4,5
// 取交集
[set1 intersectSet:set2];
NSLog(@"交集:%@",set1.allObjects); // 交集的结果为:1,2,3