In Swift 3 we redesigned condition clauses to not use the
wherekeyword; SE-0099 Restructuring Condition Clauses has the details. The upshot is that you can replace
wherein your example with a comma and it’ll work.
Clearly the Learn the Essentials of Swift tutorial should have been updated to account for this; I’d appreciate you file a bug against that, so that the folks responsible can fix this. Please post your bug number, just for the record.
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Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware
let myEmail = "eskimo" + "1" + "@apple.com"