NEW: My new book Pro SwiftUI is out now – level up your SwiftUI skills today! >>

flatMap is now (partly) compactMap()

Available from Swift 4.1

Paul Hudson      @twostraws

The flatMap() method was useful for a variety of things in Swift 4.0, but one was particularly useful: the ability to transform each object in a collection, then remove any items that were nil.

Swift Evolution proposal SE-0187 suggested changing this, and as of Swift 4.1 this flatMap() variant has been renamed to compactMap() to make its meaning clearer.

For example:

let array = ["1", "2", "Fish"]
let numbers = array.compactMap { Int($0) }

That will create an Int array containing the numbers 1 and 2, because "Fish" will fail conversion to Int, return nil, and be ignored.

Hacking with Swift is sponsored by Stream

SPONSORED Build Chat messaging quickly with Stream Chat. The Stream iOS Chat SDK is highly flexible, customizable, and crazy optimized for performance. Take advantage of this top-notch developer experience, get started for free today!

Click here

Sponsor Hacking with Swift and reach the world's largest Swift community!

Other changes in Swift 4.1…

Download all Swift 4.1 changes as a playground Link to Swift 4.1 changes

Browse changes in all Swift versions

 
Unknown user

You are not logged in

Log in or create account
 

Link copied to your pasteboard.