iosOC不可变字典和可变字典

//key 和 value 都属于(id)对象类型

//key常用字符串NSString来表示

//存储数值型 一般可用 NSString

//int  age ->@(age)

//  [dic[name] intValue];

//   @()-->转成NSNumber 类型

//     intValue

//value可以使任意对象(NSString  NSArrray , dog  )

//NSDictionary 一旦创建不能修改增加删除

#pragma mark 字典的创建

NSDictionary * dic = [[NSDictionary alloc]initWithObjectsAndKeys:

@"value1",@"key1",

@"value2",@"key2",

@"value2",@"key3",nil];

NSLog(@"%@",dic);

NSDictionary * dic1 = [NSDictionary dictionaryWithObjectsAndKeys:@"value1",@"key1", nil];

//用字典创建字典

NSDictionary * dic2 = [[NSDictionary alloc]initWithDictionary:dic];

NSLog(@"%@",dic2);

//xcode4.6

//格式: key : value 多个元素之间用,分隔

//用NSLog打印字典是不支持汉字的转码

// \U5bd2\U4ed2;

NSDictionary * dic3 =

@{@"key1":@"value1",

@"key2":@"value2",

@"key3":@"value3",

@"key4":@"value2"

};

#pragma mark 查看键的个数

NSUInteger  num = [dic2 count];

NSLog(@"%lu",num);

#pragma mark 通过key找value

NSString * str =  [dic3 objectForKey:@"key1"];

//xcode4.6

NSString * str2 = dic3[@"key2"];

NSLog(@"%@",str);

NSLog(@"%@",str2);

#pragma mark  获取所有key 所有value

NSArray * keyArray  =  [dic3 allKeys];

NSArray * valueArray = [dic3 allValues];

NSLog(@"keys = %@",keyArray);

NSLog(@"values = %@",valueArray);

#pragma mark 查看一个value对应多个key

NSArray * array =  [dic3  allKeysForObject:@"value2"];

NSLog(@"%@",array);

#pragma mark 可变字典

#pragma mark 创建可变字典

NSMutableDictionary * mutDic = [[NSMutableDictionary alloc] init];

NSDictionary * dic4 =

@{@"key1":@"value1",

@"key2":@"value2",

@"key3":@"value3",

@"key4":@"value2"

};

NSMutableDictionary * mutDic2 = [[NSMutableDictionary alloc]initWithDictionary:dic4];

#pragma mark 增加

//key不重复是增加键值对

[mutDic2 setObject:@"value3"

forKey:@"key5"];

//保证Key不重复 key必须唯一

//通过查询key的obj 是否为 ==NULL

//        if ([mutDic2 objectForKey:@"key5"]== NULL) {

//

//        }

NSDictionary * dic5 = @{@"key_1":@"value1",

@"key_2":@"value2"};

[mutDic2 addEntriesFromDictionary:dic5];

NSLog(@"%@",mutDic2);

#pragma mark 删除

//通过key删除值

[mutDic2 removeObjectForKey:@"key_1"];

NSLog(@"%@",mutDic2);

NSArray * array2 = @[@"key_2",@"key2",@"key4"];

[mutDic2 removeObjectsForKeys:array2];

NSLog(@"%@",mutDic2);

//        [mutDic2 removeAllObjects];

//        NSLog(@"%@",mutDic2);

#pragma mark 修改

//key 已存在是修改当前value的值

[mutDic2 setObject:@"hhhh" forKey:@"key1"];

NSLog(@"%@",mutDic2);

//完全覆盖掉当前字典中所有的值

[mutDic2 setDictionary:dic2];

NSLog(@"%@",mutDic2);

}