CODEWITHSUNDEEP
objective-cnsdictionary
ChrisP
ChrisP

Reputation: 10116

Can NSDictionary contain different types of objects as values?

Why does the following result in a BAD_ACCESS error?

NSDictionary *header=[[NSDictionary alloc]initWithObjectsAndKeys:@"fred",@"title",1,@"count", nil];

Can you have different types of objects as values in NSDictionary, including another NSDictionary?

Upvotes: 7

Views: 7710

Answers (4)

Jeff Kelley
Jeff Kelley

Reputation: 19071

You can put any type of object into an NSDictionary. So while @"fred" is OK, 1 is not, as an integer is not an object. If you want to put a number in a dictionary, wrap it in an NSNumber:

NSDictionary *header = { @"title": @"fred", @"count": @1 };

Upvotes: 15

Jim
Jim

Reputation: 5960

The only requirement is that is be an object. It's up to you to handle the objects properly in your code, but presumably, you can keep track of their types based on the keys.

1 is not an object. If you want t o put a number into a dictionary you may want to convert it to an NSNumber.

Upvotes: 0

Adam Rosenfield
Adam Rosenfield

Reputation: 400274

An NSDictionary can only contain Objective-C objects in it (such as NSString and NSArray), it cannot contain primitive types like int, float, or char*. Given those constraints, heterogeneous dictionaries are perfectly legal.

If you want to include a number such as 1 as a key or value, you should wrap it with an NSNumber:

NSDictionary *header=[[NSDictionary alloc] initWithObjectsAndKeys:
    @"fred", @"title",
    [NSNumber numberWithInt:1], @"count",
    nil];

Upvotes: 0

Rob
Rob

Reputation: 4239

Not the way you have it. The number 1 is a primitive and the NSArray object can hold only objects. Create a NSNumber for the "1" and then it will store it.

Upvotes: 0

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