Question

我有一个带有tableView的VC，我通过从tableView的行中多次选择项目来手动填充数组。在这个VC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，你可以在这里看到：

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此数组（selectedCategories），但是通过按下按钮以随机方式，所以我想用我的随机项填充数组var list : [QCategoryy] = [QCategoryy]()点击按钮，我该怎么办？

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())
    }
}

Answer 1

您可能想要的路线是“混乱”类别数组，然后从数组中获取第一个 n 个元素。

假设您有一组数字1到10：

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

你想得到6个随机元素。如果您只是进行了6次Get Random Element类型的通话，则很可能最终会出现重复。

因此，如果您对阵列执行Shuffle，则新阵列可能如下所示：

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

你可以得到前6个元素 - 它们是随机的，没有重复。

元素可以是任何东西......我只是在这里显示数字以供解释。

修改

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，在准备segue时，你可以这样做：

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] } } } }

可以在此处找到此随机播放及其他内容：https://stackoverflow.com/a/24029847/6257435

将随机元素添加到数组（swift）

1 个答案: