[swift] code log, day 2

iBooks 의 SWIFT 4 를 통해 언어 공부 중입니다. 이때 사용된 책 속의 코드 및 연습문제 등의 코드 로그입니다.

아래 코드들은 Github 에서도 다운받을 수 있습니다.

SWIFT_Playground_Excersice: https://github.com/youp-han/SWIFT_Playground_Excersice

//------------------------------------------------------------

// 코드 로그 입니다.

// Day 2

//Function in Function (Closure)

func makeIncrementer() -> ((Int)-> Int) {

    func addOne (number: Int) -> Int {

        return number + 1

    }

    return addOne

}

var increment = makeIncrementer()

increment(8)

//a function receives a return value from a function

//as a parameter

// Blocks of codes that call be called later

func hasAnyMatches(list:[Int], condition:(Int)->Bool)->Bool{

    for item in list {

        if condition(item){

            print("conditon true \(item)")

            return true

        }

        print("condition false, and item = \(item)")

    }

    return false

}

func lessThanTen(number: Int)-> Bool{

    return number < 10

}

var numbers = [20, 19, 7, 12]

hasAnyMatches(list: numbers, condition: lessThanTen)

// closure sample with no name

numbers.map({ (number:Int) -> Int in

    let result = 3 * number

    return result

})

let threeTimes = numbers.map({ (number:Int) -> Int in

    let result = 3 * number

    return result

})

print(threeTimes)

//experiment : the closure that returns 0 for all odd numbers in list

numbers.map({ (number:Int) -> Int in

    let result = number % 2

    if result == 0{

        return number

    }

    return 0

})

// when the type of closure is known

let mappedNumbers = numbers.map({ number in 3 * number})

print (mappedNumbers)

// parameters as numbers

let sortedNumbers = numbers.sorted { $0 > $1 }

let sortedNumbers2 = numbers.sorted { $0 < $1 }

print(sortedNumbers)

print(sortedNumbers2)