Question

我想在现有词典中插入具有相应值的键...

我能够为字典中的现有键设置值，但我无法添加新的键值......

任何帮助都将不胜感激。

Answer 1

使用NSMutableDictionary

NSMutableDictionary *yourMutableDictionary = [NSMutableDictionary alloc] init];
[yourMutableDictionary setObject:@"Value" forKey:@"your key"];

更新Swift：

以下是上述代码的确切swift副本

var yourMutableDictionary = NSMutableDictionary()
yourMutableDictionary.setObject("Value", forKey: "Key")

但我建议你使用Swift Dictionary方式。

var yourMutableDictionary = [String: AnyObject]() //Open close bracket represents initialization

//The reason for AnyObject is a dictionary's value can be String or
//Array or Dictionary so it is generically written as AnyObject

yourMutableDictionary["Key"] = "Value"

Answer 2

NSDictionnary是不可变的。请改用NSMuteableDictiory。

adding对象：setObject:forKey:

测试密钥是否存在：

[[aDict allKeys] containsObject:@"key"];

Answer 3

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

通过使用此方法，我们可以将新值添加到NSMutableDictionary

[dict setObject:@"Value" forKey:@"Key"];

知道字典中存在密钥

[[dict allKeys] containsObject:@"key"];

Answer 4

您好我以字典的格式从json获取内容，并且我将内容添加到其他字典中

  //here contract is my json dictionary 
  NSArray *projectDBList =[contract allKeys];//listing all the keys in dict 

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

  [projectDBList enumerateObjectsUsingBlock:^(NSString * obj, NSUInteger idx, BOOL *stop) {

  [projectsList setObject:[contract objectForKey:obj] forKey:obj];

  }];

如何在字典中插入具有值的新键

4 个答案: