Bartłomiej Semańczyk Bartłomiej Semańczyk - 2 years ago 268
Swift Question

"Invalid predicate: nil RHS" for second argument in NSPredicate format

This is my


let predicate = NSPredicate(format: " = %d AND (book.title CONTAINS[cd] %@ OR student.username CONTAINS[cd] %@)",, searchTextField.text!, searchTextField.text!)

The next thing I do is:

fetchedResultsController.fetchRequest.predicate = predicate
try! fetchedResultsController.performFetch() //here is the crash

The console output is:

j == 1 AND (book.title CONTAINS[cd] nil OR student.username CONTAINS[cd] "j")

And crash info is:

CRASH: Invalid predicate: nil RHS

Isn't it weird?

Answer Source

On all current iOS and OS X platforms, the C int is a 32-bit integer, and that is what the %d format expects on the variable argument list. If you pass a 64-bit integer then reading the next variable argument will read the extra 4 zero bytes.

The following table shows which format is for which integer type:

  Format   C type          Swift type
  %d       int             Int32
  %ld      long int        Int
  %lld     long long int   Int64

and similarly for the unsigned types.

Alternatively, convert the integer to a NSNumber object and use the %@ format, this works for integers of all sizes. Example:

let value = 1234
let predicate = NSPredicate(format: "value = %@", value as NSNumber)
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