How to insert a new key with value in dictionary

Question

I want to insert a key with a corresponding value in an existing dictionary...

I am able to set values for existing keys in the dictionary, but I am not able to add a new key value...

Any help would be appreciated.

Answer 1

Use NSMutableDictionary

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

Update for Swift:

The following is the exact swift replica for the code mentioned above

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

But i would suggest you to go with Swift Dictionary way.

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

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

By using this method we can add the new value to NSMutableDictionary

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

To know wheather the key exist in dictionary

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