Returning values from a closure

Closures can also return values, and they are written similarly to parameters: you write them inside your closure, directly before the in keyword.

To demonstrate this, we’re going to take our driving() closure and make it return its value rather than print it directly. Here’s the original:

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

We want a closure that returns a string rather than printing the message directly, so we need to use -> String before in, then use return just like a normal function:

let drivingWithReturn = { (place: String) -> String in
    return "I'm going to \(place) in my car"
}

We can now run that closure and print its return value:

let message = drivingWithReturn("London")
print(message)

SPONSORED Still waiting on your CI build? Speed it up ~3x with Blaze - change one line, pay less, keep your existing GitHub workflows. First 25 HWS readers to use code HACKING at checkout get 50% off the first year. Try it now for free!

Reserve your spot now

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