O'Reilly logo

Mastering Swift 4 - Fourth Edition by Jon Hoffman

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Defining an optional

One thing to keep in mind is that the type we define in the variable's declaration is actually the associated value in the optional enumeration. The following code shows us how we would typically declare an optional:

var myOptional: String? 

This code declares an optional variable that might contain a string or might contain no value (nil). When a variable such as this is declared, by default it is set to nil.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required