title: make 3 random elements in the array invisible
body: <p>I have 5 buttons in an array I want to make random three of these invisible when pressed on button. so the last two buttons will be visible</p>
  
  <p>I tried like this:</p>
  
  <pre><code> @IBAction func eliminateChoiceClicked(_ sender: Any) {
  
         let buttons:[UIButton] = [buttonA,buttonB,buttonC,buttonD,buttonE]
         let randomNumber = Int(arc4random_uniform(UInt32(3)))
         buttons[randomNumber].isHidden = !buttons[randomNumber].isHidden
  
      }
  </code></pre>
  
  <p>but it takes first elements [0,1,2] and only 1 button is invisible at each press</p>