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iOS Swift Functions and Optionals Optionals What is an Optional?

Posted by Ramon Hurtado
Ramon Hurtado
1,416 Points

Okay just a quick question to clarify so when you type the func why do you have to do "-> String?"

Okay just a quick question to clarify so when you type func findApt (aptNumber : String) -> String? { why do you have to do -> String?

1 Answer

Chase Marchione
Chase Marchione
155,055 Points
Chase Marchione
Chase Marchione
155,055 Points

Hi Ramon,

Adding a question mark after the value type tells the compiler that the return type is what is called an 'optional'. This accounts for the possibility of a 'nil', which means that there is no value set for that type.

Source: https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/Swift_Programming_Language/GuidedTour.html (Apple's Documentation... press Ctrl+F and search for 'optionals'.)

Hope this helps!