Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

iOS Closures in Swift 2 Closure Expressions Using Closure Expressions

Enid Tian
Enid Tian
7,832 Points

The Bummer! shows "Try and use a trailing closure for your closure expression" while I did wrote one. Anything wrong?

[1,2,3,4].map({(i:Int) -> Int in return i*2}) [1,2,3,4].map({i in return i*2}) [1,2,3,4].map({i in i*2}) [1,2,3,4].map({$0 * 2}) [1,2,3,4].map() {$0 * 2} [1,2,3,4].map{$0 * 2}

func doubleValue(i: Int) -> Int {
    return i * 2

let doubler = doubleValue
let doubledValues = [1,2,3,4].map(doubler)

[1,2,3,4].map({(i:Int) -> Int in return i*2})
[1,2,3,4].map({i in return i*2})
[1,2,3,4].map({i in i*2})
[1,2,3,4].map({$0 * 2})
[1,2,3,4].map() {$0 * 2}
[1,2,3,4].map{$0 * 2}

1 Answer

David Papandrew
David Papandrew
8,386 Points

You have the correct answer in your code, the only issue is that the challenge wants you to replace the "doubleValue" function call in the doubledValues statement.

So just add the trailing closure in this manner and you will pass the challenge:

let doubledValues = [1,2,3,4].map { $0 * 2 }