iOS Closures in Swift Closure Expressions Using Closure Expressions

Jobelle Galvan
Jobelle Galvan
2,970 Points

what is wrong with my code, I had a bummer says "try and use trailing closure" which I already did.

what is wrong with my code, I had a bummer says "try and use trailing closure" which I already did.

closures.swift
func double(_ i: Int) -> Int {
    return i * 2
}

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

let numbers = [1, 2, 3, 4]

numbers.map({(_ value: Int) -> Int in return value * 2})

numbers.map({value in return value * 2})

numbers.map({value in value * 2})

numbers.map({$0 * 2})

numbers.map(){ $0 * 2 }

numbers.map {$0 * 2}

1 Answer

Caleb Kleveter
MOD
Caleb Kleveter
Treehouse Moderator 37,859 Points

Sorry it took me so long to get to this, my fault.

All you need to do to pass the challenge is to modify the existing code on this line:

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

You should change the call to the map method so you use a trailing closure and the auto-generated parameter name.