//1.创建一个可变长度字典        NSMutableDictionary * muDic = [[NSMutableDictionary alloc] initWithCapacity:0];        //2.向字典中村如数据        [muDic setObject:@"1" forKey:@"one"];        [muDic setObject:@"2" forKey:@"two"];        [muDic setObject:@"3" forKey:@"three"];                NSLog(@"muDic %@",muDic);                //3.删除        [muDic removeObjectForKey:@"one"];                NSLog(@"muDic %@",muDic);                //4.全部删除        [muDic removeAllObjects];                NSLog(@"muDic %@",muDic);                        Student * stu1 = [[Student alloc] initWithName:@"xiaoher" andAge:20];        Student * stu2 = [[Student alloc] initWithName:@"alex" andAge:50];        Student * stu3 = [[Student alloc] initWithName:@"xiaoli" andAge:10];                [muDic setObject:stu1 forKey:@"s1"];        [muDic setObject:stu2 forKey:@"s2"];        [muDic setObject:stu3 forKey:@"s3"];        //在向字典中存储数据的时候,一定要保证key值是唯一的//        [muDic setObject:stu3 forKey:@"s3"];//        [muDic setObject:stu3 forKey:@"s3"];//        [muDic setObject:stu3 forKey:@"s3"];                    NSLog(@"muDic %@",muDic);                        //1.使用for循环遍历字典        NSArray * allkeys = [muDic allKeys];                for (int i = 0; i < allkeys.count; i++)        {            NSString * key = [allkeys objectAtIndex:i];            Student * stu = [muDic objectForKey:key];            NSLog(@"stu %@",stu);        };                //2.使用枚举器                NSEnumerator * enumerator = [muDic objectEnumerator];        Student * tmp;        while (tmp = [enumerator nextObject]) {            NSLog(@"tmp %@",tmp);        }