Question

As someone who has some programming experience it pains me to be asking this question. I just started playing around with objective-c a few days ago and I am trying to simply add NSNumber objects to an NSDictionary. The problem is, when I add an NSNumber object with a negative value it seems as if it is being added as a string not an NSNumber.

Here is how I am initializing the dictionary:

testDict = [[NSDictionary alloc] initWithObjectsAndKeys:[NSNumber numberWithDouble:-3],@"x",
                                        [NSNumber numberWithDouble:7, @"a",
                                    nil];

I guess I really have two questions, 1.) Is this not how you create an NSNumber object that has a negative value?

2.) When I print out the dictionary I get the following:

NSLog(@"dictionary = %@", self.testDict);

a = 7;
x = "-3";

Why the double quotes around the -3?

Answer 1

You’re correct, and everything’s fine. That’s just the dictionary -description being misleading.

To verify, break on the NSLog() and try (warning: typed on iPhone):

p [testDict objectForKey:@"x"];

It should reveal it to be an NSNumber instance.