Objective-C -> 删除 NSDictionary 中的最后一个元素

Question

编辑：

编码：

//存储问题字典

- (void)requestFinished:(ASIHTTPRequest *)request
{   
    NSData *responseData = [request responseData];
    NSString *json = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
    NSDictionary *qs = [json objectFromJSONString]; 
    self.questions = qs;
    NSLog(@"%@", questions);
    [json release]; 
    [self setQuestions];
    [load fadeOut:load.view withDuration:0.7 andWait:0];
    UIBarButtonItem *anotherButton = [[UIBarButtonItem alloc] initWithTitle:@"Start" style:UIBarButtonItemStylePlain target:self action:@selector(start:)];          
    self.navigationItem.rightBarButtonItem = anotherButton;
}

我在 NSDictionary 中有以下项目：

(
   {
        max = 120;
        min = 30;
        question = "Morning Bodyweight (Kg)";
        questionId = 1;
        questionNumber = 1;
        sectionId = 1;
        type = TextInput;
    },
    {
        question = "Morning Urine Colour";
        questionId = 2;
        questionNumber = 2;
        sectionId = 1;
        type = ImagePicker;
    },
    {
        max = 120;
        min = 30;
        question = "Evening Bodyweight (Kg)";
        questionId = 3;
        questionNumber = 3;
        sectionId = 1;
        type = TextInput;
    },
    {
        question = "Evening Urine Colour";
        questionId = 4;
        questionNumber = 4;
        sectionId = 1;
        type = ImagePicker;
    },
    {
        max = 90;
        min = 40;
        question = "Morning Heart Rate (BPM)";
        questionId = 5;
        questionNumber = 5;
        sectionId = 1;
        type = TextInput;
    },
    {
        question = "Time of Month (TOM)";
        questionId = 6;
        questionNumber = 6;
        sectionId = 1;
        type = Option;
    }
)

我想删除最后一个元素：

    {
        question = "Time of Month (TOM)";
        questionId = 6;
        questionNumber = 6;
        sectionId = 1;
        type = Option;
    }

NSDictionary 是否有等效的 pop()？ 如果不是，如何删除最后一个元素？

Answer 1

字典没有顺序，所以没有“最后一个对象”

但是，这可能会解决您的问题，尽管它可能并不总是删除您认为“最后一个对象”是什么：

[dictionaryName removeObjectForKey:[[dictionaryName allKeys] lastObject]];

Answer 2

字典中没有最后一个元素，因为字典中的元素没有排序。

Answer 3

这看起来是（或可能是）一个字典数组。 如果您将这些字典作为NSMutableArray的对象，那么您可以使用– removeLastObject 。 否则，您就是 SOL，因为即使NSMutableDictionary也没有这种方法。

Answer 4

您可以通过使用键值以某种方式获取元素吗？ NSDictionaries 没有排序，因此没有删除“最后一个”元素这样的事情。

Answer 5

我认为这是您自己获得的一系列 NSDictionaries。 在这种情况下，很容易做到：

NSMutableArray *mArray = [NSMutableArray arrayWithArray:array]; // if not mutable
[mArray removeLastObject];