- (void)makeObjectsPerformSelector:(SEL)aSelector withObject:(id)anObject 遍历数组，向数组每个元素发送消息(SEL)aSelector， (id)anObject是这个方法的参数。 - (void)makeObjectsPerformSelector:(SEL)aSelector

- (void)makeObjectsPerformSelector:(SEL)aSelector;- (void)makeObjectsPerformSelector:(SEL)aSelector withObject:(id)argument; 这是 NSArray和NSSet的两个方法，相信大家很少用，它类似于 for循环，但有效率高于for循环 makeObjects