is it true that the key values for NSMutableDictionary can only be strings?
I was trying to use objects, but I am getting a warning.
+4
A:
From the docs:
In general, a key can be any object (provided that it conforms to the NSCopying protocol—see below), but note that when using key-value coding the key must be a string (see Key-Value Coding Fundamentals).
What warning are you getting?
Joshua Nozzi
2009-12-31 03:40:25
as it turned out my class did not implement the protocal
Mel
2009-12-31 03:49:16
yeah - definitely make sure you implement the "hash" method in your object. Otherwise, you can get two different objects appearing identical in the dictionary.
Ben Gotow
2009-12-31 06:21:40
+2
A:
You can use any object, but the object must implement -[NSObject hash], -[NSObject isEqual:], and the NSCopying protocol.
Tom Dalling
2009-12-31 03:41:03
well all objects that inherit from NSObject implement `-hash`. it is only if you override `-isEqual:` that you have to make sure the `-hash` is compatible with `-isEqual:`
newacct
2009-12-31 04:27:39
A:
If you take a look at header file of NSMutableDictionary, the add function can take id as the key:
- (void)setObject:(id)anObject forKey:(id)aKey;
- (void)removeObjectForKey:(id)aKey;
So you can use virtually anything as the key and value.
umerh
2009-12-31 05:42:10