Simple Fact App: How do I write code so the fact does not repeat itself consecutively?

Question

func randomFact() -> String {
        let randomNumber = GKRandomSource.sharedRandom().nextInt(upperBound: facts.count)
        return facts[randomNumber]

That is the code for randomizing the facts. However, how can I modify the code so the fact does not repeat itself till all the other facts are displayed?

Answer 1 · 2018-07-10T13:57:27Z

July 10, 2018 1:57pm

A simple solution would be to do something like this:

func randomFact() -> String {
let randomNumber = GKRandomSource.sharedRandom().nextInt(upperBound: facts.count)

if facts.count == 0 {
   facts = [...] // here you have to restore the facts array to its original state
   return facts.remove(at: randomNumber)
} else {
       return facts.remove(at: randomNumber)
       }
}

The problem with this approach is that it could create the same result twice once in a while when you restore the array. But its guarantied to be more random than before since you always remove the latest result.

Answer 2 · 2018-08-13T21:03:43Z

August 13, 2018 9:03pm

Here's my solution... it's a little lengthy but it's guaranteed to NOT repeat 'facts'.

After hours of scratching my head about this problem I finally was telling a friend about it (unconsciously rubberducking) and I found the error in my code. Anyways, that's beside the point. Here's the resulting code...

// Initialize: Get a fact to test
        var currentFact = factProvider.randomFact()
        var currentFactIndex = factProvider.getIndex(ofFact: currentFact)
 //       var newFact: String

        // Create a counter
        var y = 0
        var counter = 0

        // If all the facts have been displayed...
        if  displayedFactsIndexes.count > factProvider.facts.count {
            // Do nothing
        } else {
            if displayedFactsIndexes.count != factProvider.facts.count {
                while y < displayedFactsIndexes.count {
                    if currentFactIndex == displayedFactsIndexes[y] {
                        // Get new fact
                        currentFact = factProvider.randomFact()
                        currentFactIndex = factProvider.getIndex(ofFact: currentFact)

                        // Set y back to 0 to retry all possibilities
                        y = 0
                    } else {
                        // DEBUG
                        print("This fact: \(currentFact) has made it through \(y) tries.")
                        print("This loop has repeated \(counter) times!")
                        y += 1
                    }

                    counter += 1
                }
                // Set the current fact to the text
                funFactLabel.text = currentFact

                // Add the fact index to the displayed array
                displayedFactsIndexes.append(currentFactIndex)

            } else {
                funFactLabel.text = "All out of fun facts!"
            }
        }

Basically I kept an array of the indexes of the 'used' facts. So the array would look something like this...

displayedFactsIndexes = [2, 5, 10, 3]
// The array would look like this if you saw the index numbers first...
// 0: 2, 1: 5, 2: 10, 3: 3

This array enabled me to check the generated fact's index number with the already used facts array numbers. I did this instead of checking the generated fact with an array of the already used facts just because it seemed simpler and dealt with a smaller unit (integer rather than a string), but this would work just as well check the strings with one another.

y is the starting index number for the used facts array... for when the generated fact is being compared to all the used facts. y increases by 1 for every time the generated fact is comfirmed that it's not equal to the used fact the if function is checking. y is set back to zero if the generated fact and one of the used facts are equal. Then a new fact is generated and the process is started all over again.

That's pretty much it. There's some debugging code in there that might make things a little confusing. Let me know if you have any questions.

G'day!

Gavin Hobbs

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Abhi Agar

Abhi Agar

Simple Fact App: How do I write code so the fact does not repeat itself consecutively?

2 Answers

Magnus Hållberg

Magnus Hållberg

Gavin Hobbs

Gavin Hobbs