Foundation框架中的 字典

//创建不可变字典

    NSDictionary *dic = [[NSDictionary alloc]initWithObjectsAndKeys:val1,key1,val2

    ,key2,val3,key3,nil];

    //类创建字典

    NSDictionary *dic2 = [NSDictionary dictionaryWithObjectsAndKeys:val1,key1,val2

                          ,key2,val3,key3,nil];

    

    

    NSArray *key = @[key1,key3,key2,key4];

    NSArray *value = @[val1,val3,val2,val4];

    NSDictionary *dic3 =

    [[NSDictionary alloc]initWithDictionary:dic];

    

    

    NSDictionary *dic4 = [[NSDictionary alloc]initWithObjects:key forKeys:value];

    

   //--------------字典的使用------------

    NSArray *obj1 = [dic objectForKey:@"门派"];//根据key获取value

    NSUInteger count = [dic count];//字典元素的个数

    

    NSArray *allkey = [dic allKeys];//获取字典中所有的key;

    //字典的遍历

    for (int i =0;i< dic.count;i++){

        NSString *key = allkey[i];//获取key

        id val = [dic objectForKey:key];//通过key获取value

        NSLog(@"%@,%@",key,value);

    

    

    }

    //for in  遍历

    for (NSString *key in dic2) {

        id val = [dic2 objectForKey:key];

        NSLog(@"%@",val);

    }

//快速创建字典

    NSDictionary *dic5 = @{key1:val1,key2:val2};

    

    id value1 = dic5[key1];//快速获取元素

    

    

    

//创建可变字典

    NSMutableDictionary *mdic = [[NSMutableDictionary alloc]initWithCapacity:5];

    

    //类方法创建

    NSMutableDictionary *mdic2 = [NSMutableDictionary dictionaryWithCapacity:10];

    

    //添加元素

    [mdic setObject:@"wangba" forKey:@"k1"];

    [mdic setObject:@"laji" forKey:@"k2"];

    NSLog(@"mdic = %@",mdic);

    

    //key 如果存在会覆盖原来的value

    [mdic setObject:@"bie" forKey:@"k1"];

     NSLog(@"mdic = %@",mdic);

    

    // 删除 通过key删除value

    [mdic removeObjectForKey:@"k1"];

    NSLog(@"mdic = %@",mdic);

    //全部删除

    [mdic removeAllObjects];

    NSLog(@"mdic = %@",mdic);