Notice: Undefined index: understanding-swift in /var/sites/hackingwithswift.com/site/src/Controller/NewBooksReadController.php on line 89
Why does Swift have string interpolation? - a free tutorial

NEW: Start my new Ultimate Portfolio App course with a free Hacking with Swift+ trial! >>

Why does Swift have string interpolation?

Paul Hudson    @twostraws   

When it comes time to showing information to your user – whether that’s messages being printed out, text on buttons, or whatever fits your app idea – you will usually rely heavily on strings.

Of course, we don’t just want static strings, because we want to show the user some sort of relevant data they can use. So, Swift gives us string interpolation as a way of injecting custom data into strings at runtime: it replaces one or more parts of a string with data provided by us.

For example:

var city = "Cardiff"
var message = "Welcome to \(city)!"

Of course, in that trivial example we could have just written our city name directly into the string – “Welcome to Cardiff!” – but in real apps having this inserted dynamically is important because it lets us show real-world user data rather than things we typed ourselves.

Swift is capable of placing any kind of data inside string interpolation. The result might not always be useful, but for all of Swift’s basic types – strings, integers, Booleans, etc – the results are great.

Tip: String interpolation is extremely powerful in Swift. If you’re keen to see just what it can do, check out this more advanced blog post from me: https://www.hackingwithswift.com/articles/178/super-powered-string-interpolation-in-swift-5-0

Hacking with Swift is sponsored by ViRE

SPONSORED ViRE offers discoverable way of working with regex. It provides really readable regex experience, code complete & cheat sheet, unit tests, powerful replace system, step-by-step search & replace, regex visual scheme, regex history & playground. ViRE is available on Mac & iPad.

Download on the App Store

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

BUY OUR BOOKS
Buy Pro Swift Buy Swift Design Patterns Buy Testing Swift Buy Hacking with iOS Buy Swift Coding Challenges Buy Swift on Sundays Volume One Buy Server-Side Swift (Vapor Edition) Buy Advanced iOS Volume One Buy Advanced iOS Volume Two Buy Advanced iOS Volume Three Buy Hacking with watchOS Buy Hacking with tvOS Buy Hacking with macOS Buy Dive Into SpriteKit Buy Swift in Sixty Seconds Buy Objective-C for Swift Developers Buy Server-Side Swift (Kitura Edition) Buy Beyond Code

Was this page useful? Let us know!

 
Unknown user

You are not logged in

Log in or create account
 

Link copied to your pasteboard.