NEW! Pre-order my latest book, Testing Swift! >>

How to use map() with an optional value

Paul Hudson       @twostraws

The map() method of optionals allows you to transform the optional if it has a value, or do nothing if it is empty. This makes for shorter and more expressive code than doing a regular unwrap, and doesn’t require you to change your data type.

For example, if you had an optional string like this one:

let name: String? = "twostraws"

You could use the map() method to transform it safely, without having to check and unwrap it – if it were nil, the map() call would do nothing.

For example:

let twitterName = name.map { "@\($0)" }
print(twitterName)

That will print @twostraws.

Available from iOS – learn more in my book Pro Swift

Did this solution work for you? Please pass it on!

Other people are reading…

About the Swift Knowledge Base

This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.

Need to know Objective-C fast?

I wrote a book dedicated to teaching Objective-C to developers who already know Swift – it's the fastest way to get up to speed!

MASTER SWIFT NOW
Buy Testing Swift Buy Practical iOS 12 Buy Pro Swift Buy Swift Design Patterns Buy Swift Coding Challenges Buy Server-Side Swift (Vapor Edition) Buy Server-Side Swift (Kitura Edition) Buy Hacking with macOS Buy Advanced iOS Volume One Buy Advanced iOS Volume Two Buy Hacking with watchOS Buy Hacking with tvOS Buy Hacking with Swift Buy Dive Into SpriteKit Buy Swift in Sixty Seconds Buy Objective-C for Swift Developers Buy Beyond Code

Was this page useful? Let me know!

Click here to visit the Hacking with Swift store >>