Unclear understand of ? : in swift syntax

Question

I can't quite comprehend this syntax in the return statement. I'm not sure if it is new in Swift 2.0, but what does the ? and the : mean? Is this question mark an optional, even though spaced? Im quite confused, coming from an Objective-C background.

private func doContainsUser(user: User) -> Bool {
    let isInverted = setOfDiff.contains(user)
    let wasInitiallyAdded = setOfCircleUsers.contains(user)

    //What does the ? and the : mean?
    return isInverted ? !wasInitiallyAdded : wasInitiallyAdded
}

Ternary operator (see also conditional operator, inline if (iif), or ternary if.). More info there: https://en.wikipedia.org/wiki/%3F: In other words: if (isInverted){return !!wasInitiallyAdded}else{ return wasInitiallyAdded} Swift Doc (that explain it also): https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/BasicOperators.html#//apple_ref/doc/uid/TP40014097-CH6-ID71 — Larme, Jun 09 '16 at 15:51
Really? It is _exactly_ the same in Objective-C! https://en.wikipedia.org/wiki/%3F: — matt, Jun 09 '16 at 15:51
Why would you not just `return wasInitiallyAdded ^ isInverted` — Alexander, Jun 09 '16 at 16:06
@Larme To be clear, this is not *the* ternary operator. This is the *conditional operator*, which is *a* ternary operator. But it also happens to be the only ternary operator at the moment. — Alexander, Jun 09 '16 at 16:17

score 5 · Accepted Answer · answered Jun 09 '16 at 15:51

5

This is a short hand if else statement.

if isInverted {
   return !wasInitiallyAdded
}
else {
   return wasInitiallyAdded
}

answered Jun 09 '16 at 15:51

egfconnor

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oh makes so much sense now. thank u – Josh O'Connor Jun 09 '16 at 15:52

Unclear understand of ? : in swift syntax

1 Answers1