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iOS Closures in Swift 2 Closure Expressions Using Closure Expressions

Anthony Kim
Anthony Kim
4,010 Points
Posted by Anthony Kim
Anthony Kim
4,010 Points

what is my fault?!

i already add trailing cloure.

but they keey said to me u should add trailing cloure.

so im just confuseed

what is my fault in my code.

plz help mee~

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

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

doubledValues.map({ (i: Int) -> Int in return i * 2 })
doubledValues.map({ i in return i * 2 })
doubledValues.map({ i in i * 2 })
doubledValues.map({ $0 * 2 })
doubledValues.map() { $0 * 2 }
doubledValues.map{ $0 * 2 }

3 Answers

Florian Laplanche
Florian Laplanche
4,476 Points
Florian Laplanche
Florian Laplanche
4,476 Points 
func doubleValue(i: Int) -> Int {
    return i * 2
}

let doubler = doubleValue
let doubledValues = [1,2,3,4].map {$0 * 2}
Anthony Kim
Anthony Kim
4,010 Points
Anthony Kim
Anthony Kim
4,010 Points

Thank u for ur Answerr~

Have a nice day Friends~

Florian Laplanche
Florian Laplanche
4,476 Points
Florian Laplanche
Florian Laplanche
4,476 Points

All you have to do is change the existing map function to have a trailing closure like this

let doubledValues = [1,2,3,4].map {$0 * 2}
Anthony Kim
Anthony Kim
4,010 Points
Anthony Kim
Anthony Kim
4,010 Points

already change like this but they keep said to me "Try and use a trailing closure for your closure expression" 

<p>This is code!</p>
let doubledValues = [1,2,3,4].map({ (i: Int) -> Int in return i * 2 })
let doubledValues = [1,2,3,4].map({ i in return i * 2 })
let doubledValues = [1,2,3,4].map({ i in i * 2 })
let doubledValues = [1,2,3,4].map({ $0 * 2 })
let doubledValues = [1,2,3,4].map() { $0 * 2 }
let doubledValues = [1,2,3,4].map { $0 * 2 }
Florian Laplanche
Florian Laplanche
4,476 Points
Florian Laplanche
Florian Laplanche
4,476 Points

you don't need to add all that code. From the original code provided, deleted the doubler function call from map and put the {$0 * 2} trailing closure