Question

我如何从下面的字典中获得“狗”？

{
  Id = "123";
  Animal = [{
     Id = "456";
     Type = "Dog";
     Sound = "Bark";
  },
  {
     Id = "789";
     Type = "Cat";
     Sound = "Meow";
  }]
}

我试过

NSString *firstAnimalType = dictionary[@"Animal"][@"Type"];

然而，由于有多只动物，它无法识别我想要找到的东西。如何将第一只动物从列表中取出以便我可以访问它的类型？谢谢！

Answer 1

你可以使用这样的东西，首先得到动物对象，如果它存在，那么从中找到它的类型

NSDictionary *firstAnimal = [dictionary[@"Animal"] firstObject];
if(firstAnimal) //in case your firstAnimal is Empty or it may be nil then may create any unwanted issues in further code so just check it first.
{
   NSString *firstAnimalType = firstAnimal[@"Type"];
}

Answer 2

枚举方法将有所帮助，您可以随时随地停止

[myDict[@"Animal"] enumerateObjectsUsingBlock:^(id  _Nonnull objList, NSUInteger idx, BOOL * _Nonnull stop) {

       NSLog(@"%@",objList[@"Type"]);            
        *stop = YES; //You can stop where you want

}];

Answer 3

您只需使用castings访问数组的第一个元素并获取其Type值。

NSString *firstAnimalType = ((NSDictionary *)[((NSArray *)dictionary[@"Animal"]) objectAtIndex: 0])[@"Type"];

Answer 4

for (NSDictionary *animal in dictionary[@"Animal"]) {
   NSString *type = animal[@"Type"];
   if ([type isKindOfClass:[NSString class]] && [type isEqualToString:@"Dog"]) {
    // Dog found
   }
}

Answer 5

你走了：

NSArray *aryFinalAni = [dicMain valueForKey:@"Animal"];
NSArray *aryType = [aryFinalAni valueForKeyPath:@"Type"];
if([aryType containsObject:@"Dog"])
{
    int indexOfDog = (int)[aryType indexOfObject:@"Dog"];
    NSMutableDictionary *dicDog = [aryFinalAni objectAtIndex:indexOfDog];
    NSLog(@"%@",dicDog);
}
else
{
    NSLog(@"There is no Dog found.");
}

Answer 6

试试这段代码：

{
 Id = "123";
 Animal = [{
      Id = "456";
      Type = "Dog";
      Sound = "Bark";
    },
    {
      Id = "789";
      Type = "Cat";
      Sound = "Meow";
  }]
}

1> NSArray *items = dictionary["Animal"];
2>
   NSPredicate *predicate1 = [NSPredicate predicateWithFormat:                                 @"Type CONTAINS[cd] %@", "Dog"];
   NSArray *arrData  = [items filteredArrayUsingPredicate:predicate1];

   if arrData.count > 0 {
        dictionary = [arrData objectAtIndex:0];
   }


Result:
{
  Id = "456";
  Type = "Dog";
  Sound = "Bark";
}

NSDictionary在对象列表中获取属性 - 目标C.

6 个答案: