Binary operators with optionals in Swift 3

Question

I have lots of code in my project of this style:

let hasQuestionsRemaining = user.numberOfCredits > 0.0

where numberOfCredits is a Double?. So I get the error : Binary operator '>' cannot be applied to operands of type 'Double?' and 'Double'.

So now I use:

var hasQuestionsRemaining = false
if let numberOfCredits = user.numberOfCredits, numberOfCredits > 0.0 {
   hasQuestionsRemaining = true
}

Is there a more efficient way to do this?

Compare http://stackoverflow.com/questions/39427650/swift3-optionals-chaining-in-if-conditions-bug. — Martin R, Sep 28 '16 at 14:42

score 0 · Answer 1 · edited Sep 28 '16 at 17:18

In Swift 2.2, you used to be able to compare Optional and non-Optional types directly, but that behaviour has been removed in Swift 3.0. You can read more about it in proposal SE-0121.

Swift 3.0 leaves it to developers to handle their optionals in a way that's most appreciate to their application. In your case, this seems like the way to go:

let hasQuestionsRemaining = user.numberOfCredits ?? 0.0 > 0.0

It'll treat nil values as 0.0 for the sake of comparison to 0.0.

Binary operators with optionals in Swift 3

1 Answers1