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iOS Closures in Swift 2 Closure Expressions Using Closure Expressions

Enid Tian
Enid Tian
7,832 Points
Posted by 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}

closures.swift 
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
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 }