Objective-C: Convert id to NSInteger

Question

I have a dictionary with an NSNumber in it and I'd like to convert it into NSInteger. Is the simplest/shortest way to do this is to typecast into NSNumber and then calling integerValue? Like so:

// newQuestion is an NSDictionary defined somewhere
NSInteger questionId = [(NSNumber *)[newQuestion objectForKey:@"question_id"] integerValue];

Is there a better way to do this? Thanks!

Answer 1

You can get rid of the cast if you want to make it shorter:

// newQuestion is an NSDictionary defined somewhere
NSInteger questionId = [[newQuestion objectForKey:@"question_id"] integerValue];

Since objectForKey: returns id, you can send it any known message and the compiler won't complain.

Answer 2

Yes, you don't need to cast.

NSInteger questionId = [[newQuestion objectForKey:@"question_id"] integerValue];

The cast doesn't actually do anything in this particular case. If the item in your dictionary is not a NSNumber (e.g., it's nil), then questionId will be 0.

Answer 3

Nope. That is the way to go. The question, though, is why do you need to turn into an integer in the first place? That may be avoidable. Or not.