Creating NSPredicate dynamically by setting the key programmatically

Question

Why does the former of following snippets work while not the latter ?

Snippet 1

NSPredicate *predicate = [NSPredicate predicateWithForma         


        

Answer 1

I got the following error even though my NSPredicate was formatted correctly.

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Insufficient arguments for conversion characters specified in format string.' site:stackoverflow.com

Like a fool I forgot to pass a second argument to the predicate format (because there were two %@). I.e. NSPredicate(format:predicateFormat,argumentArray:[Date()]) has only one element in the array when it needs to be two: [Date(), Date()]