ios - 如何跟踪数组中的哪些项目已经存在？

Question

我有一个生成随机问题的测验应用程序。目前由于随机化，您有时可以多次回答同一个问题。我有一系列问题，我使用 arc4Random 方法在屏幕上生成一个随机问题。

我如何才能让 swift 识别出一个问题已经存在并跳过它？我必须做一个 if 声明吗？如果是这样，我将如何编码？

var currentQuestion = Int(arc4random_uniform(31) + 1)
var rightAnswerPlacement:UInt32 = 0
var seconds = 30
var timer = Timer()
var score = 0
if (sender.tag == Int(rightAnswerPlacement)) {
    score += 1
    scoreLabel.text = "\(score)"
    seconds = 100
    currentQuestion = Int(arc4random_uniform(32) + 1)
} else {
    timer.invalidate()
    end()
}

Answer 1

var currentQuestion = Int(arc4random_uniform(36) + 1)
var rightAnswerPlacement:UInt32 = 0
var seconds = 30
var timer = Timer()
var score = 0
var asked = [Int]()

var recordData:String!

@IBOutlet weak var questionLabel: UILabel!
@IBOutlet weak var timeLabel: UILabel!
@IBOutlet weak var scoreLabel: UILabel!

@IBOutlet weak var buttonOne: UIButton!
@IBOutlet weak var buttonTwo: UIButton!
@IBOutlet weak var buttonThree: UIButton!

@IBAction func answerButtons(_ sender: AnyObject) {

    if (sender.tag == Int(rightAnswerPlacement)) {

        score += 1
        scoreLabel.text = "\(score)"
        seconds = 100
        currentQuestion = Int(arc4random_uniform(36) + 1)

       while asked.contains(currentQuestion) {

            currentQuestion = Int(arc4random_uniform(36) + 1)
        }
        asked.append(currentQuestion)
        print(asked)

        if asked.count == questions.count {
            currentQuestion = 0
          return
        }