objective-c字典

1 // 初始化一个空字典

2 // NSDictionary *dictionary = [[NSDictionary alloc] init];

3 // 初始化一个空典

4 // NSDictionary *dictionary1 = [NSDictionary dictionary];

5 // 初始化的同时 添加一对键值

6 // NSDictionary *dictionary2 = [NSDictionary dictionaryWithObject:@"value" forKey:@"key"];

7 // 初始化的同时添加多对键值

8 // 前面是值 可以是任意类型

9 // 后面是key 必须是字符串

10 NSDictionary *dictionary3 = [NSDictionary dictionaryWithObjectsAndKeys:@"object",@"key",@"object1",@"key1", @"object2",@"key2",nil];

11 // 字典的新方法

12 // 前面是key 后面是值 与之前的方法的键值相反

13 NSDictionary *dictionary4 = @{@"key":@"值",@"key1":@"值1"};

14 NSLog(@"%@",dictionary3);

15 NSLog(@"%@",dictionary4);

16

17 // objectForKey ：通过key曲字典里面的值

18 NSLog(@"%@",[dictionary4 objectForKey:@"key"]);

19 // 第二种取值方式

20 NSLog(@"%@",dictionary4[@"key1"]);

21

22

23 // 1用字典 表达出自己的考试分数 语文 25 数学 1000 英语 3

24

25 NSDictionary *scrose = [NSDictionary dictionaryWithObjectsAndKeys:@"25",@"chinese",@"1000",@"math",@"3",@"English", nil];

26 [scrose objectForKey:@"chinese" ];

27 [scrose objectForKey:@"math"];

28 [scrose objectForKey:@"English"];

29 NSLog(@"%@ %@ %@",[scrose objectForKey:@"chinese" ],[scrose objectForKey:@"math"],[scrose objectForKey:@"English"]);

30 NSDictionary *year = [NSDictionary dictionaryWithObjectsAndKeys:@"发芽",@"春",@"开花",@"夏",@"结果",@"秋",@"凋谢",@"冬",@"发芽1",@"春1",@"开花1",@"夏1",@"结果1",@"秋1",@"凋谢1",@"冬1", nil];

31 // 输出一个key对应的值

32 NSLog(@"%@",[year objectForKey:year.allKeys[0]]);

33 // 遍历所有的键值

34 // allKeys是所有 key的一个数组

35 // count得到数字内有多少个元素

36 for(NSString *key in year.allKeys){

37 NSLog(@"%@ %@",key,[year objectForKey:key]);

38 }

39

40

41 NSLog(@"%@ %@ %@ %@",[year objectForKey:@"春"],[year objectForKey:@"夏"],[year objectForKey:@"秋"],[year objectForKey:@"冬"]);

42

执行结果：