1 extension UIFont { 2 class func fontName(fontName: String, size fontSize: CGFloat) -> UIFont { 3 4 return UIFont(name: fontName, size: fontSize)! 5 } 6 } 7 class ViewController: UIViewController { 8 9 override func viewDidLoad() { 10 super.viewDidLoad() 11 // Do any additional setup after loading the view, typically from a nib. 12 self.navigationItem.title = "Swift" 13 14 ///1.常量 15 let number: Int = 10 16 print("the number is (number)") 17 //1.1变量 18 var string :String = "hello world!" 19 print("(string.count)个字符") 20 //1.2检查字符串是否有特定前缀/后缀:hasPrefix/hasSuffix 21 if string.hasPrefix("hello") { 22 print("hello首部") 23 } 24 if string.hasSuffix("!"){ 25 print("!在尾部") 26 } 27 //1.3空字符串 28 string = ""; 29 if string.isEmpty { 30 print("空字符串") 31 }else{ 32 print("非空字符") 33 } 34 //1.4 元组 35 let myproject = (one:"game",two:12345) 36 print("myproject:(myproject)") 37 38 //1.3 获取随机数 39 let temp:Int = Int(arc4random()%100) + 1; 40 print(temp) 41 let temps : Int = Int(arc4random_uniform(100)) + 1; 42 print(temps) 43 44 /// 创建label 45 let label = UILabel.init(frame: CGRect.init(x: 10, y: 15 + TOP_HEIGHT, SCREEN_WIDTH - 20, height: 30)) 46 label.text = "the number is (number)" 47 label.backgroundColor = RED_COLOR; 48 label.textColor = GREEN_COLOR 49 label.font = UIFont.fontName(fontName: "PingFangSC-Regular", size: 14) 50 view.addSubview(label) 51 var variableNumber = 42 52 variableNumber = 24 53 print("the variableNumber is (variableNumber)") 54 55 56 57 }