Question

我试图从letters中获取26个中的20个随机值，这些值也必须包含数组name中的元素。 finalArray看起来像是：["S", "A", "M", "A", "N", "T", "H", "A", "I", "J", "K", "L", "S", "N", "O","P","Q", "R", "S", "A"]（随机）

到目前为止：

var letters: [String] = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O","P","Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"]


var name: [String] = ["S", "A", "M", "A", "N","T","H","A"]


//Create finalArray elements

var availableLetters = letters.filter { value in
    !contains(name, value)
}

var finalArray = availableLetters + name

我试着这样做：

    //get 20 objects
var length = name.utf16Count

var beforeArray = finalArray[0...19]

//minus length of the word

var letterCount = beforeArray.count - length

// add missing letters
beforeArray = letters[0...letterCount] + name

这显然是错误的，结果非常不稳定。我可以使用什么作为简单的解决方法？我怎么能实现它？

Answer 1

从您的示例中可以看出，您想要取name，然后用字母表中的随机字母右键填充它，长度为20.因为看起来您不介意重复随机字母，这使事情变得容易多了。

棘手的部分是生成一系列n个随机数，最大值。如果你有这个，你可以使用这些数字作为字母数组的索引来选择随机字符。这是生成该序列的一种方法：

// Struct representing a sequence of count
// random numbers in range 0..<max
struct RandomSequence: SequenceType {
    let count: Int
    let max: Int
    func generate() -> GeneratorOf<Int> {
        var i = 0
        return GeneratorOf {
            i++ < self.count
              ? Int(arc4random_uniform(UInt32(self.max)))
              : nil
        }
    }
}

一旦你有了它，它就可以用来生成填充：

let name = Array("SAMANTHA")
let alphabet = Array("ABCDEFGHIJKLMNOPQRSTUVWXYZ")

let targetCount = 20
let paddingCount = targetCount - name.count

let ranseq = RandomSequence(count: paddingCount, max: alphabet.count)
let padding = map(ranseq) { alphabet[$0] }

let padded = name + padding
// padded = ["S", "A", "M", "A", "N", "T", "H", "A", "W", "O", "C", "M", "L", "B", "L", "A", "N", "H", "I", "I"]

如果您确实希望随后使用随机字母填入名称，请查看this question的最佳答案。但这可能是最简单的做法，作为上述技术的第二步，而不是尝试将两个步骤结合在一起。

值得注意的是，如果name是一个字符串，并且您希望结果以字符串形式结束，那么您无需为此方法添加数组：

let name = "SAMANTHA"
let alphabet = Array("ABCDEFGHIJKLMNOPQRSTUVWXYZ")

let targetCount = 20
let paddingCount = targetCount - count(name)

let ranseq = RandomSequence(count: paddingCount, max: alphabet.count)
let padding = map(ranseq) { alphabet[$0] }

let padded = name + padding
// padded = "SAMANTHASLHMPRDYRHFC"

从数组中获取多个值？

1 个答案: