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 Want to try Swift on microcontrollers? MadMachine provides ways to interact with the physical world in a Swift way. Join us and have fun!

Get it now

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