Hard to believe anyone would use that as an example. In C# you could do:

filteredArray = allRecords.Find(i => i.someField == filterValue)

EDIT: Not sure why the downvote, I'm simply stating that many other languages have far better syntax for filtering an array so I'm not sure why the author would think the syntax in Obj-c is all that great unless they have never done the same thing in any other language.