nhathm

//: Playground - noun: a place where people can play
// nhathm01247@gmail.com

import UIKit

// Basic function declare
func sayHi() {
    print("Hi")
}
sayHi()

nhathm

struct Student {
    let name: String?
    let age: Int?
    let gender: String?
}

let student = Student(name: "Rio", age: 27, gender: "Male")

func validateStudentInfo (_ student: Student) -> String {
    // We do NOT need to using student name, just want to check if

nhathm

let name : String? = "Swift"
let version : Int = 3
let owner : String = "Apple"

func checkMultiCondition(name : String?, version : Int, owner : String) {
    guard let name = name, version > 2, owner == "Apple" else {
        print("Input parameters not match!!!")
        return
    }
    print(name)

nhathm

let name : String? = "Swift"
let nickName : String? = nil

// Example: Optional binding
// Note: underscore "_" using to ignore name of parameter when call function
// Example calling function below
func sayHiWithOptionalBinding(_ name: String?) {
    // Using optional binding to check if object is NOT nil
    if let checkName = name {
        // If not nil, do some logic...

nhathm

// Declare non-optionals variable
var notToday : String = "Tomorrow"

// Can't set non-optionals variable to nil
notToday = nil // Compile error

// Declare optionals variables
var dafug : String? = "Dafug"
var steps : Int? = 10

nhathm

// Get priview image for video
func previewImageFromVideo(_ url: URL) -> UIImage? {
    let asset = AVAsset(url: url)
    let imageGenerator = AVAssetImageGenerator(asset: asset)
    imageGenerator.appliesPreferredTrackTransform = true
    
    var time = asset.duration
    time.value = min(time.value, 2)
    
    do {