views:

149

answers:

2

I'm using an NSSortDescriptor to sort NSDate objects in an ascending order. However, I need nil dates to be at the bottom of the list, whereas at the moment they come at the top.

+2  A: 

Of course, I should use

initWithKey:ascending:selector:

and write my own comparison selector

Daniel Wood
Exactly. Do you custom logic to handle nil values and then call [myNSDateInstance compare:secondDate]; if second date is non nil.
Corey Floyd
That won't help, since `compare:` will be sent to the NSDate instances; if `nil` ends up the receiver, the result will be `NSOrderedSame`, and if the receiver is not `nil` but the argument is, I don't think any specific result is guaranteed.
Peter Hosey
+1  A: 

In the end I have decided that having nil values is not a good idea and if I want what were nil value to appear at the bottom of the ascending list I should set the dates to [NSDate distantFuture] and them check for this before displaying them. It turns out this makes more semantic sense in within the applications as well.

Daniel Wood