Not Repeating Word in Swift when clicking button - IOS - ios

Question

How can I not repeat the array when I click on the button in swift? I'm trying to generate fruits without them repeating.
import UIKit
class fruitrandomViewController: UIViewController {
#IBOutlet weak var nextfruitButton: UIButton!
#IBOutlet weak var fruitbox: UILabel!
#IBAction func fruitbutton(_ sender: UIButton) {
let array = ["Apple","Banana","Orange","Pinapple", "Plum", "Pear",]
let randomFruitgenerator = Int(arc4random_uniform(UInt32(array.count)))
fruitbox.text = array[randomFruitgenerator]
}
}

Answer 1

My suggestion is to use a Set and remove the random item from the set
var set = Set(["Apple","Banana","Orange","Pinapple", "Plum", "Pear"])
#IBAction func fruitbutton(_ sender: UIButton) {
if let fruit = set.randomElement() {
fruitbox.text = fruit
set.remove(fruit)
} else {
fruitbox.text = "" // or whatever to indicate that the set is empty
}
}

Answer 2

My suggest:
You can random each item 1 time
let originFruits = ["Apple","Banana","Orange","Pinapple", "Plum", "Pear"]
let array = originFruits
#IBAction func fruitbutton(_ sender: UIButton) {
...
let fruitRandom = array random
array delete fruitRandom
if (array empty) {
array = originFruits
}
}
You can check and remove in next time
let originFruits = ["Apple","Banana","Orange","Pinapple", "Plum", "Pear"]
let array = originFruits
let skipFruit = ""
#IBAction func fruitbutton(_ sender: UIButton) {
...
array = originFruits
array delete skipFruit
let fruitRandom = array random
skipFruit = fruitRandom
}

Answer 3

I think this will work, but I think it's Time Complexity can be O(n) as I am assuming that there is a possibility of randomElement return Apple every time and savedFruit is also Apple, so in that case, the Time Complexity will be O(n). A better workaround will be to remove that element from that array so, the next time the randomElement will be different for sure. Then, once it is different you can append the old one and remove the current one. I hope it makes sense to you, but for now this will work I think:
let array = ["Apple","Banana","Orange","Pinapple", "Plum", "Pear"]
var savedFruit = String()
func fetchRandomFruit() {
if let fruit = array.randomElement() {
if fruit != savedFruit { //Here it will check if the last element is same as the new randomElement
savedFruit = fruit
fruitbox.text = savedFruit
} else {
fetchRandomFruit()
}
}
}
#IBAction func fruitbutton(_ sender: UIButton) {
fetchRandomFruit()
}

Answer 4

Use fruitbox.text = array.randomElement() ?? "default value for if array is empty". This is not guaranteed not to repeat, but is random.
If you want to ensure it does not repeat, use this
var new = array.randomElement() ?? fruitbox.text
while new == fruitbox.text {
new = array.randomElement() ?? fruitbox.text
}
fruitbox.text = new
This WILL loop infinitely (until it crashes) if the array is empty.