import Cocoa

/* Create a simple closure */
let sayHello = {
    print("Hello, World!")
}

/* Call the closure */
sayHello()

/* Create a function that can take a closure as a parameter */
func sayHelloTo(name: String, withGreeting greeting: () -> ()) {
    print("Hello, \(name)!")
    greeting()
}

/* Call the function, passing in the closure */
sayHelloTo(name: "John", withGreeting: sayHello)

Output

Hello, World!

Hello, John!

Hello, World!

import Cocoa

/* Create a array of months from Jan to Jun */
var months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun"]
print(months)

/* Create a function to swap random elements in the array */
func swapRandomElements(array: inout [String]) {
    let firstIndex = Int(arc4random_uniform(UInt32(array.count)))
    let secondIndex = Int(arc4random_uniform(UInt32(array.count)))
    let temp = array[firstIndex]
    array[firstIndex] = array[secondIndex]
    array[secondIndex] = temp
}

/* swap the months */
swapRandomElements(array: &months)
print(months)

/* swap the months 2 times */
swapRandomElements(array: &months)
swapRandomElements(array: &months)
print(months)

/* swap the months 10 times */
for _ in 1...10 {
    swapRandomElements(array: &months)
}
print(months)

Output

["Jan", "Feb", "Mar", "Apr", "May", "Jun"]

["Jan", "Apr", "Mar", "Feb", "May", "Jun"]

["Jan", "Mar", "Jun", "Feb", "May", "Apr"]

["May", "Apr", "Jun", "Feb", "Mar", "Jan"]

import Cocoa

/* Create a uuid */
let uuid = UUID().uuidString
print(uuid)

/* remove dashes from uuid */
let uuidWithoutDashes = uuid.replacingOccurrences(of: "-", with: "")

print(uuidWithoutDashes)

/* remove all characters from the uuid */
let uuidWithoutAllCharacters = uuidWithoutDashes.replacingOccurrences(of: "[A-Z]", with: "", options: .regularExpression)

print(uuidWithoutAllCharacters)

/* get the last character from the uuid */
let lastCharacter = uuidWithoutAllCharacters.last
print(lastCharacter!)

/* check if the last character is a even or odd number */
let isEven = Int(String(lastCharacter!))! % 2 == 0
print(isEven)

Output

985BCADD-D907-4D19-B48A-22A1D8067704

985BCADDD9074D19B48A22A1D8067704

985907419482218067704

4

import Cocoa

/* Create an array of 5 intergers with duplicate values */
let array = [1, 2, 3, 4, 5, 1, 2, 3, 4, 5]
print(array)

/* remove duplicate values from the array */
let set = Set(array)
print(set)

Output

[1, 2, 3, 4, 5, 1, 2, 3, 4, 5]

[4, 1, 5, 2, 3]

import Cocoa

/* Create an array of 2 negative integers */
var negativeIntegers = [-1, -2]

/* print the array */
print(negativeIntegers)

/* Create an array of 2 positive integers */
var positiveIntegers = [1, 2]

/* print the array */
print(positiveIntegers)

/* Merge the two arrays */
var allIntegers = negativeIntegers + positiveIntegers

/* print the array */
print(allIntegers)

Output

[-1, -2]

[1, 2]

[-1, -2, 1, 2]

import Cocoa

/* Create an array of 5 integers */
var myArray = [1, 2, 3, 4, 5]

/* print the array */
print(myArray)

/* using closure, add 1 to each element of the array */
myArray = myArray.map({$0 + 1})

/* print the array */
print(myArray)

Output

[1, 2, 3, 4, 5]

[2, 3, 4, 5, 6]

import Cocoa

/* Swift: Add 2 numbers using function */
func addNumbers(num1: Int, num2: Int) -> Int {
    return num1 + num2
}

print(addNumbers(num1: 1, num2: 2))

/* Swift: Add 2 numbers using closure */

let addNumbersClosure = { (num1: Int, num2: Int) -> Int in
    return num1 + num2
}

print(addNumbersClosure(1, 2))

Output

3

3

import Cocoa

/* Create a function that takes a string and returns a string. */
func sayHello(name: String) -> String {
    return "Hello \(name)!"
}
/* print the result of calling sayHello with "Cocoa" as the argument. */
print(sayHello(name: "Cocoa"))

/* Create a closure that takes a string and returns a string. */
let sayHelloClosure = { (name: String) -> String in
    return "Hello \(name)!"
}
/* print the result of calling sayHelloClosure with "Cocoa" as the argument. */
print(sayHelloClosure("Closure"))

Output

Hello Cocoa!

Hello Closure!

import Cocoa

/* Create an array of 5 integers */

var myArray = [1, 2, 3, 4, 5]

/* Using reduce, sum the values in the array */

var sum = myArray.reduce(0, +)

/* Print the sum */
print(sum)

Output

15

import Cocoa

/* How many friday the 13th in the year 2023? */
let year = 2023
let calendar = Calendar.current
let dateComponents = DateComponents(year: year, month: 1, day: 1)
let date = calendar.date(from: dateComponents)!
let range = calendar.range(of: .month, in: .year, for: date)!
let months = range.count
var friday13th = 0
for month in 1...months {
    let dateComponents = DateComponents(year: year, month: month, day: 13)
    let date = calendar.date(from: dateComponents)!
    let weekday = calendar.component(.weekday, from: date)
    if weekday == 6 {
        friday13th += 1
    }
}
print(friday13th)

Output

2