动态视图调整标签文本Swift

Question

我想要发生的是矩形视图将调整标签的长度。这是我的代码

   @IBOutlet weak var rectangleView: UIView!
    @IBOutlet weak var label: UILabel!

override func viewDidLoad() {
        super.viewDidLoad()

  let stringNumber = "123ewrqrqwerw4"
        let numberFromString = Int(stringNumber)

  rectangleView.frame = CGRect(x: 15, y: 100, width: self.view.frame.width * numberFromString, height: 50)
   self.label.text =  stringNumber
}

但我的代码错了。