OC总结之字典

// 1.创建字典
        NSDictionary *jack = [[NSDictionary alloc] initWithObjectsAndKeys:
                              @"jack", @"name", @"18", @"age", nil];
        
        // 2.快速创建字典，比较常用
        NSDictionary *jack1 = @{
                                @"name":@"jack",
                                @"age":@"18"
                                };
        NSLog(@"%p %p",jack,jack1);
        NSLog(@"jack = %@ jack1 = %@",jack,jack1);
        
        NSNumber *number = [NSNumber numberWithInt:21];
        NSArray *array = @[@"one",@"two",@"three"];
        
        // 3.在字典中存储数据时没有顺序
        NSDictionary *dic = @{
                              @"array":array,
                              @"number":number,
                              @"dic":jack1
                              };
        NSLog(@"dic = %@",dic);
        
        // 4.获取字典长度
        NSUInteger count = [dic count];
        NSLog(@"字典长度为 = %lu",count);
        
        
        // 5.从字典中取值
//        Returns the value associated with a given key.
//        返回键对应的值
        NSArray *arrayInDic = [dic objectForKey:@"array"];
        NSLog(@"字典中的array = %@",arrayInDic);
        
        NSDictionary *dicInDic = [dic objectForKey:@"dic"];
        NSLog(@"字典中的dic = %@",dicInDic);
        
        NSNumber *numberInDic = [dic objectForKey:@"number"];
        NSLog(@"字典中的number = %@",numberInDic);



        // 1.快速创建的字典和数组都是不可变的
        // 值，键，值，键...
        NSMutableDictionary *mutableDic = [[NSMutableDictionary alloc]initWithObjectsAndKeys:@"jack",@"name",@"18",@"age", nil];
        NSLog(@"mutableDic = %@",mutableDic);
        

        // 2.如何向字典中'插入'一个数据
        
        Person *person = [[Person alloc]init];
        NSString *string = [[NSString alloc]initWithFormat:@"18"];
//        - (void)setObject:(id)anObject forKey:(id <NSCopying>)aKey;
        [mutableDic setObject:person forKey:@"height"];
        NSLog(@"count = %ld",[person retainCount]);// strong reference 就要释放掉
        [person release];
        
//        [string release];
        NSLog(@"mutableDic = %@",mutableDic);
        //        The value for aKey. A strong reference to the object is maintained by the dictionary. Raises an NSInvalidArgumentException if anObject is nil.// 键对应值，字典会强引用这个对象，
        // 3.删除
        [mutableDic removeObjectForKey:@"name"];
        NSLog(@"%@",mutableDic);

//        // 4.全部删除
//        [mutableDic removeAllObjects];
//        NSLog(@"mutableDic = %@",mutableDic);
        
        // 5.遍历字典
        // 获取字典中所有的键
       NSArray *keysArray =  [mutableDic allKeys];
        // 获取字典中所有的值
        NSArray *valuesArray = [mutableDic allValues];
//        Returns a new array containing the dictionary’s values.
//The order of the values in the array isn’t defined.
        // 返回包含字典中值的新数组  数组中值的顺序没有被定义
        for (id key in keysArray) {
            NSLog(@"key = %@",key);
            id value = mutableDic[key]; // 获取某个key的值
            NSLog(@"value = %@",value);
        }
        
        //