OC 自带方法 简绍 6 NSSet

1.set  // 集

例子

        Person * p = [[Person alloc] initWithName:@"阿顺" sex:@"男" age:30];
        Person * p1 = [[Person alloc] initWithName:@"啊寿" sex:@"男" age:30];
        Person * p2 = [[Person alloc] initWithName:@"阿福" sex:@"男" age:30];
        Person * p3 = [[Person alloc] initWithName:@"啊幸" sex:@"男" age:25];
        Person * p4 = [[Person alloc] initWithName:@"啊吉" sex:@"男" age:25];
        Person * p5 = [[Person alloc] initWithName:@"阿运" sex:@"男" age:25];
        Person * p6 = [[Person alloc] initWithName:@"阿帅" sex:@"男" age:25];

2. setWithObjects  // 创建集并添加元素

+ (instancetype)setWithObjects:(id)firstObj  // Creates and returns a set containing the objects in a given argument list.

例子:

        NSSet * set = [NSSet setWithObjects:p, p1, p2, p3, p4, p5, p6, nil];
        NSLog(@"set = %@", set);

3.anyObject //从集中随机得到一个元素

@property(nonatomic, readonly) id anyObject //One of the objects in the hash table. (read-only)

例子

        NSSet * set = [NSSet setWithObjects:p, p1, p2, p3, p4, p5, p6, nil];
        NSLog(@"set = %@", set);

4.NSMutableSet //可变的集合