O'Reilly logo

Swift Functional Programming - Second Edition by Dr. Fatih Nayebi

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

Optional mapping

Mapping over an array would generate one element for each element in the array. Can we map over an optional to generate non-optional values? If we have some, map it; otherwise, return none. Let's examine the following code:

func mapOptionals<T, V>(transform: (T) -> V, input: T?) -> V? {     switch input {     case .some(let value): return transform(value)     case .none: return .none     } } 

Our input variable is a generic optional and we have a transform function that takes input and transforms it into a generic type. The result will be a generic optional type. In the function body, we use pattern matching to return the respective values. Let's test this function:

class User {     var name: String? } 

We create a class named User with ...

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