How to modify only one Key-Value pair in an NSMutableDictionnary

If I have an NSMutableDictionnary with 4 Key Value pairs (stored in a .plist), When I load the dictionary from the .plist how can I开发者_开发知识库 modify only one of the Key Value Pairs without erasing the rest?

You can change a single value for the given key like so:

[dict setValue:@"value" forKey:@"key"];

[dictionary setObject:value forKey:key] will assign the value for the specified key; [dictionary removeObjectForKey:key] will remove the key-value pair completely.