我有一个 VC，里面有一个 tableView，我通过从 tableView 的行中多次选择项目来手动填充一个数组。在这个 VC 中我有一个数组

var list : [QCategoryy] = [QCategoryy]()
list = NearbyPlaces.getCategories()

其中 getCategories() 是

static func getCategories() -> [QCategoryy] {
        let list:[QCategoryy] = [QCategoryy(name: "bar", image: UIImage(named: "bar_button.png")!), QCategoryy(name :"night_club", image: UIImage(named: "nightclub_button.png")!), QCategoryy(name: "movie_theater", image: UIImage(named: "cinema_button.png")!), QCategoryy(name: "restaurant", image: UIImage(named: "restaurant_button.png")!), QCategoryy(name: "gym", image: UIImage(named: "gym_button.png")!), QCategoryy(name: "spa", image: UIImage(named: "spa_button.png")!), QCategoryy(name: "museum", image: UIImage(named: "museum_button.png")!)]
        return list
    }

这些项目(酒吧、健身房、水疗中心等)将填充我的 tableView 单元格，当我选择它们时，我将创建我的数组 selectedCategories 你如何在这里看到:

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

        if segue.identifier == nearbySearchSegueIdentifier {
            let selectedCategories: [QCategoryy] = tableView.indexPathsForSelectedRows?.map({ (indexPath) -> QCategoryy in
                return list[indexPath.row] }) ?? []

            if let selectedRows = tableView.indexPathsForSelectedRows {

                if let vc : nextClass = segue.destination as? nextClass {


                vc.categories = selectedCategories


            }
        }
    }
}

现在我想知道如何在不选择 tableView 的单元格的情况下填充这个数组 (selectedCategories)，而是通过按一个按钮随机填充数组，所以我想用随机填充数组我的 var list 的项目:[QCategoryy] = [QCategoryy]() 用按钮点击，我该怎么做？

更新

struct QCategoryy {
    var name: String
    var image: UIImage
    var isSelected = false

    init(name:String, image:UIImage) {
        self.name = name
        self.image = image

    }
}

extension QCategoryy: ExpressibleByStringLiteral {


    init(stringLiteral value: String) {
        self.name = value
        self.image = UIImage()

    }
    init(unicodeScalarLiteral value: String) {
        self.init(name: value, image: UIImage())
    }
    init(extendedGraphemeClusterLiteral value: String) {
        self.init(name: value, image: UIImage())
    }
}

最佳答案

您可能想要走的路线是“打乱”类别数组，然后从数组中取出前 n 个元素。

假设您有一个数字数组 1 到 10:

[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

并且您想获得 6 个随机元素。如果您简单地执行了 6 次 Get Random Element 类型的调用，您很可能会以重复项结束。

因此，如果您对数组执行随机播放，您的新数组可能如下所示:

[7, 2, 9, 5, 3, 4, 1, 10, 8, 6]

您可以获得前 6 个元素 - 这将是随机的，没有重复。

元素可以是任何东西......我只是在这里显示数字来进行解释。

编辑

例如...将此代码添加到您的项目中:

extension MutableCollection where Indices.Iterator.Element == Index {
    /// Shuffles the contents of this collection.
    mutating func shuffle() {
        let c = count
        guard c > 1 else { return }

        for (firstUnshuffled , unshuffledCount) in zip(indices, stride(from: c, to: 1, by: -1)) {
            let d: IndexDistance = numericCast(arc4random_uniform(numericCast(unshuffledCount)))
            guard d != 0 else { continue }
            let i = index(firstUnshuffled, offsetBy: d)
            swap(&self[firstUnshuffled], &self[i])
        }
    }
}

extension Sequence {
    /// Returns an array with the contents of this sequence, shuffled.
    func shuffled() -> [Iterator.Element] {
        var result = Array(self)
        result.shuffle()
        return result
    }
}

然后，为 segue 做准备，您可以:

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

        if segue.identifier == nearbySearchSegueIdentifier {
            if let vc : nextClass = segue.destination as? nextClass {

                // use ALL QCategoryy objects, in random order
                vc.categories = NearbyPlaces.getCategories().shuffled()

                // or, use 4 random QCategoryy objects
                //vc.categories = NearbyPlaces.getCategories().shuffled()[0...3]

            }
        }
    }
}

可以在此处找到此 shuffle 扩展和其他扩展:https://stackoverflow.com/a/24029847/6257435

关于ios - 将随机元素添加到数组(swift)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/47308761/