NSDictionary 总结 -iOS

总结：字典分NSDictionary（不可变，只能查询）和NSMutableDictionary（可变。能增删改查）两种，形式是key-value，key是不可重复的，value可以重复

1.初始化字典

        NSDictionary *dic1 = [[NSDictionary alloc] init];
        NSDictionary *dic2 = [[NSDictionary alloc] initWithObjectsAndKeys:@"yun",@"name", @"f",@"gender", @18,@"age", nil];
        NSLog(@"%@",dic1);
        NSLog(@"%@",dic2);

2.往字典里加key-value 和根据key找value

 [dic setObject:@"yun" forKey:@"name"];

 NSString *name = [dic objectForKey:@"name"];

3.获取字典中所有的key

NSArray *keys = dic.allKeys;
//或者
NSArray *keys = [dic allKeys];

4.获取所有的value

 NSArray *values = [dic allValues];
//或者
 NSArray *values = dic.allValues;

5.删除字典中某个值 或者 全部删除

[dic removeObjectForKey:@"name"];

[dic removeAllObjects];

1 将model转换成字典

//将model转换成字典
    NSDictionary *dictionary=[loginM toDictionary];
    NSMutableDictionary *dic= [dictionary mutableCopy];
    [dic removeObjectForKey:@"sign"];