Realm: Filter with IN Operator

Question

I have an array of Integers:

▿ 2 elements
  - [0] : 123459
  - [1] : 1031020

And would like to filter my objects based on the array.

.filter("code IN \(myCodeArray)")

But this results in a crash. How do I use the IN operator correctly?

Answer 1

Instead of using Swift's string interpolation, you should use NSPredicate's argument substitution support via %@:

.filter("code IN %@", myCodeArray)

Swift's string interpolation syntax ("\(someVariable)") inserts a string representation of the variable into the string. The string representation of your array of integers is [123459, 1031020], which is not valid in an NSPredicate format string. Using %@ substitutes the object into the predicate without needing to worry about whether the Swift string representation of the object matches what NSPredicate expects.