Difference between objectForKey and valueForKey?

Question

What is the difference between objectForKey and valueForKey? I looked both up in the documentation and they seemed the same to me.

Answer 1

As said, the objectForKey: datatype is :(id)aKey whereas the valueForKey: datatype is :(NSString *)key.

For example:

 NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:[NSArray arrayWithObject:@"123"],[NSNumber numberWithInteger:5], nil];

 NSLog(@"objectForKey : --- %@",[dict objectForKey:[NSNumber numberWithInteger:5]]);  
    //This will work fine and prints (    123    )  

 NSLog(@"valueForKey  : --- %@",[dict valueForKey:[NSNumber numberWithInteger:5]]); 
    //it gives warning "Incompatible pointer types sending 'NSNumber *' to parameter of type 'NSString *'"   ---- This will crash on runtime. 

So, valueForKey: will take only a string value and is a KVC method, whereas objectForKey: will take any type of object.

The value in objectForKey will be accessed by the same kind of object.