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

Accepting parameters in a closure

When you create closures, they don’t have a name or space to write any parameters. That doesn’t mean they can’t accept parameters, just that they do so in a different way: they are listed inside the open braces.

To make a closure accept parameters, list them inside parentheses just after the opening brace, then write in so that Swift knows the main body of the closure is starting.

For example, we could make a closure that accepts a place name string as its only parameter like this:

let driving = { (place: String) in
    print("I'm going to \(place) in my car")
}

One of the differences between functions and closures is that you don’t use parameter labels when running closures. So, to call driving() now we’d write this:

driving("London")
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!

Average rating: 4.8/5

 
Unknown user

You are not logged in

Log in or create account
 

Link copied to your pasteboard.