//for each 
let numbersInWord = ["One", "Two", "Three", "Four", "Five", "Six"]
numbersInWord.forEach { 
   element in print(element)
}

//map()

let numbers = [1, 2, 3, 4, 5, 6, 7]
let numbersInString = numbers.map { 
   number in String(number)
}
print("numbersInString: \(numbersInString)")

//compactmap()
let numbersInString = ["1", "x2", "3", "4", nil, "five5"]
let validNumbers = numbersInString.compactMap { 
    stringValue in
    Int(stringValue ?? "")
}
print("validNumbers: \(validNumbers)")

//flatmap()
let marks = [[3, 4, 5], [2, 5, 3], [1, 2, 2], [5, 5, 4], [3, 5, 3]]
let allMarks = marks.flatMap { 
   marksArray -> [Int] in
   marksArray
}
print("allMarks: \(allMarks)")

//filter
let numbers = [-12, 23, -1, 56, 9, -2, 0, 14, 8]
let positives = numbers.filter { 
   number in
   number > 0
}
print("positives: \(positives)")

//reduce()
let numbers = [1, 5, 2, 10, 6]
let sum = numbers.reduce(0) { 
   (result, number) -> Int in
   result + number
}
print("sum:", sum)
//sort
var numbers = [1, 5, 2, 10, 6]
numbers.sort()
print("Sorted numbers: \(numbers)")