OCNSDictionary

/*字典：散列表，无序的集合，字典通过键值对（key,value）存储数据*/

              //初始化                       //一般初始化(一般初始化用键值对)        NSDictionary *dictionary = [[NSDictionary alloc]initWithObjectsAndKeys:                                    @"1",@"key1",                                    @"2",@"key2",                                    @"3",@"key3",                                    @"4",@"key4",                                    @"5",@"key5",                                    @"6",@"key6",                                    nil];        NSLog(@"%@",dictionary);        NSArray *array = [NSArray arrayWithObjects:@"1",@"2",@"3",@"4",@"5",@"6", nil];        NSLog(@"%@",array);                 //便利初始化                NSDictionary *dictionary1 = [NSDictionary dictionaryWithObjectsAndKeys:                                     @"1",@"key1",                                     @"2",@"key2",                                     @"3",@"key3",                                     @"4",@"key4",                                     @"5",@"key5",                                     @"6",@"key6",                                     nil];        //字典取值 :通过制定的key 获取对应的值，键是唯一的                NSString *string = [dictionary objectForKey:@"key1"];//取到1        NSLog(@"%@",string);                //求空间大小        NSUInteger count = [dictionary count];        NSLog(@"%ld",count); //6        //获取所有键(得到的是无序的)字典本身就是无序的        NSArray *keys = [dictionary allKeys];        NSLog(@"%@",keys);        //获取所有值 (去除所有值放在数组里面)        NSArray *values = [dictionary allValues];        NSLog(@"%@",values);