使用arc4random生成十个随机数

Question

我arc4random用来生成10个随机数,这样我就可以查询firebase来获取包含随机生成数字的问题.问题是我不希望任何数字出现多次,因此没有重复的问题.目前的代码如下......

import UIKit
import Firebase

class QuestionViewController: UIViewController {

    var amountOfQuestions: UInt32 = 40

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.

        // Use a for loop to get 10 questions
        for _ in 1...10{
            // generate a random number between 1 and the amount of questions you have
            let randomNumber = Int(arc4random_uniform(amountOfQuestions - 1)) + 1
            print(randomNumber)
            // The reference to your questions in firebase (this is an example from firebase itself)
            let ref = Firebase(url: "https://test.firebaseio.com/questions")
            // Order the questions on their value and get the one that has the random value
            ref.queryOrderedByChild("value").queryEqualToValue(randomNumber)
                .observeEventType(.ChildAdded, withBlock: {
                    snapshot in
                    // Do something with the question
                    print(snapshot.key)
                })
        }
    }

    @IBAction func truepressed(sender: AnyObject) {
    }

    @IBAction func falsePressed(sender: AnyObject) {
    }
}

Answer 1

您可以使用一个数组来存储您想要随机的值,在您的情况下,[1,2,3 .... 10],然后使用arc4random获取内部任何值的随机索引(0..9 ),获取值并从数组中删除它.然后你永远不会从数组中得到相同的数字.