OC06 -- 字典

一. 创建不可变字典的方式:

//字典的字面量,前key后value

    NSDictionary *dic =@{@"1":@"2",@"3":@"4"};

NSDictionary *dic = [[NSDictionaryalloc]init];

NSDictionary *dic = [NSDictionary dictionary];

NSDictionary *dic = [[NSDictionary alloc]initWithObjectsAndKeys:@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",nil];  

NSLog(@"%@",dic);

 // Key 是唯一的,可是Value是能够反复的

 // key 不能为空.

二. 不可变字典的属性与方法:

//1.属性:有多少键值对 -- count:

    NSLog(@"%ld",dic.count);

// 2. objectForKey -- 依据Key找value:

    NSLog(@"%@",[dic objectForKey:@"2"]);

    NSLog(@"%@",dic[@"2"]);

//3. 获取全部的key和value --

    NSLog(@"%@",dic.allKeys);

    NSLog(@"%@",dic.allValues);

三. 创建可变字典的方式:

   NSMutableDictionary *dic = [NSMutableDictionarydictionaryWithObjectsAndKeys:@"1",@"2",@"3",@"4",@"5",@"6",nil]; 

   // 遍历字典.

     打出全部Vaule

   for (NSInteger i = 0; i < dic.allKeys.count; i++) {

        NSLog(@"%@",dic.allValues[i]);

    }

   for (NSString *str in dic) {

        NSLog(@"%@",str);// 打出字典的Key.

        NSLog(@"%@",dic[str]);//打出Vaule.

    }

四.可变字典的属性与方法: 

NSMutableDictionary *dic1 = [[NSMutableDictionaryalloc]initWithObjectsAndKeys:@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",nil];

//1.可变键值对加入(当key不存在时就进行加入,当key存在时,就进行vaule值的改动.) -- setObject forKey:

    [dic1setObject:@"10"forKey:@"11"];

    NSLog(@"%@ ",dic1);

    [dic1setObject:@"1000"forKey:@"11"];

   NSLog(@"%@",dic1);

//2. 移除键值对

    [dic1 removeObjectForKey:@"8"];

   NSLog(@"%@",dic1); 

//3. 所有移除

    [dic1 removeAllObjects];

   NSLog(@"%@",dic1);

//4. setObject 是字典自己方法,setVaule是KVC的方法,即使效果一样,但以后对字典进行操作还用setObject.

    [dic1setValue:@"100"forKey:@"10"];

五.字典与数组的嵌套:

//1. 字典里对象是数组.

   NSArray *arr1 = @[@"1",@"2",@"3",@"4"];

   NSArray *arr2 = @[@"5",@"6",@"7",@"8"];

    NSMutableDictionary *dic = [NSMutableDictionarydictionaryWithObjectsAndKeys:arr1,@"arr1",arr2,@"arr2",nil];

    // 遍历.

 for (NSString *keyin dic) {

   // 针对相应的key 找到vaule,vaule是一个数组,所以用一个数组对象来接受.

       NSLog(@"%@",key);

       NSArray *arr = dic[key];

     for (NSString *vaulein arr) {

         NSLog(@"%@",vaule);

       }

   }

//2. 数组里对象是字典.

   NSDictionary *dic1 = [NSDictionarydictionaryWithObjectsAndKeys:@"杨林",@"name",@"19",@"age",nil];

    NSDictionary *dic2 = [NSDictionarydictionaryWithObjectsAndKeys:@"刘鑫狗",@"name",@"20",@"age",nil];

    

    NSDictionary *dic3 = [NSDictionarydictionaryWithObjectsAndKeys:@"刘伊茹",@"name",@"0",@"age",nil];

   NSArray *arr = @[dic1,dic2,dic3];

    

   for (NSDictionary *dicin arr) {

       for (NSString *keyin dic) {

           NSLog(@"%@",dic[key]);

        }

    }

   

六.三层嵌套的练习:

   NSDictionary *dic1 = [NSDictionarydictionaryWithObjectsAndKeys:@"杨林",@"name",@"19",@"age",nil];

    NSDictionary *dic2 = [NSDictionarydictionaryWithObjectsAndKeys:@"刘鑫狗",@"name",@"20",@"age",nil];

    NSDictionary *dic3 = [NSDictionarydictionaryWithObjectsAndKeys:@"刘伊茹",@"name",@"0",@"age",nil];

   NSArray *arr1 = @[dic1,dic2];

   NSArray *arr2 = @[dic3];

   NSDictionary *Bdic = [NSDictionarydictionaryWithObjectsAndKeys:arr1,@"arr1",arr2,@"arr2",nil];

   for (NSString *keyBin Bdic) {

       NSArray *arr =Bdic[keyB];

       for (NSDictionary *sdicin arr) {

           for (NSString *keyin sdic) {

               NSLog(@"%@",sdic[key]);

            }

        }

    }