How to randomize the questions in my quiz app?

Hi!

I'm making one of my first apps, a kind of quiz.

The structure of the questions looks like this:

struct Question {
let text: String
let answers: [Answer]   
}

struct Answer {
let text: String
let correct: Bool
}

How can I make the questions appear in a random order? Would it be necessary to change the structure of the questions and answers?

assuming you have your questions in an array, you can use the shuffled method to get a new array with the contents shuffled, or a shuffle method to shuffle it in place (remember to make it a var instead of let if you want to shuffle in place).

let allQuestions = [
    Question(text: "Life, the Universe and Everything", answers: [
        Answer(text: "42", correct: true),
        Answer(text: "What?", correct: false),
    ]),
    Question(text: "Monoid in the category of endofunctors", answers: [
        Answer(text: "Tuple", correct: false),
        Answer(text: "Monad", correct: true),
    ]),
]

let questionsInRandomOrder = allQuestions.shuffled()

@cukr Thank you!

Assuming you have some huge array with all of your questions, and you want to get a small number of random elements without duplicates, I would do something like this:

let questionDatabase: [Question] = ...
let questionsPerQuiz = 10

// Select some random indexes, without duplicates.
var selectedQuestionIndexes: Set<Int> = []
while selectedQuestionIndexes.count < questionsPerQuiz {
  selectedQuestionIndexes.insert(questionDatabase.indices.randomElement())
}

// Get the question from each selected index.
// Shuffle again because they are returned in hash-table order.
var quiz: [Question] = selectedQuestionIndexes.lazy.map { idx in 
  questionDatabase[idx] 
}.shuffled()

This allows you to avoid copying and shuffling the entire database when you only want a few items.

That being said, pure randomness might not actually make the most fun quiz; good question selection can make a big difference. There's often some level of structure behind it - like maybe having separate easy/medium/hard question pools, and mixing them a little (so maybe there's a 5% chance of a hard question in medium mode), or having separate categories so you can control how often particular topics appear (randomness could give you 10 geography questions in a row). So try things out!

@Karl Thank you!

I think there is a mistake here, so that the questions are not shuffled. What should I change?

    override func viewDidLoad() {
    super.viewDidLoad()
    table.delegate = self
    table.dataSource = self
    QuestionsInRandomOrder()
    ConfiqureUI(question: allQuestions.first!)
}


private func ConfiqureUI(question: Question){
    label.text = question.text
    CurrentQuestion = question
    table.reloadData()
}

I have about 400 questions, so as not to make it boring and lengthy, I would love it if only 20, 50 or 100 random questions are shown in random order. How can I do this?

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