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")
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!
Sponsor Hacking with Swift and reach the world's largest Swift community!
Link copied to your pasteboard.