单击按钮时在 Swift 中不重复单词 - IOS

Question

当我快速单击按钮时，如何不重复数组？我试图在不重复的情况下产生水果。

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

我的建议是使用Set 并从集合中删除随机项

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

我的建议：

你可以随机每个项目1次

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
  }
}

您可以在下次检查并删除

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

我认为这会起作用，但我认为Time Complexity 可以是O(n)，因为我假设randomElement 有可能每次都返回Apple 并且savedFruit 也是Apple，所以在这种情况下，Time Complexity 将是O(n)。更好的解决方法是从array 中删除该元素，因此，下次randomElement 肯定会有所不同。然后，一旦它不同，您可以附加旧的并删除当前的。我希望这对你有意义，但现在我认为这会起作用：

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

使用fruitbox.text = array.randomElement() ?? "default value for if array is empty"。这不是保证不会重复，而是随机的。

如果你想确保它不重复，使用这个

var new = array.randomElement() ?? fruitbox.text
while new == fruitbox.text {
    new = array.randomElement() ?? fruitbox.text
}
fruitbox.text = new

如果数组为空，这个WILL会无限循环（直到崩溃）。