在Swift中拖拽一个字符串

Question

我正在尝试使用Swift为iPhone创建一个单词jumbler游戏。我对编程和Swift比较陌生，但以前用Python创建过这个游戏。

这是我的伪代码：

//select RANDOM WORD from array

//determine the number of characters in the RANDOMLY SELECTED WORD

//randomly select a NUMBER within the boundries of the number of characters (i.e. if the word is "apple," select a number between 0 and 4)

//select the CHARACTER that corresponds to the randomly selected NUMBER

//add the CHARACTER to a new string (JUMBLE)

//remove the CHARCATER from the RANDOMLY SELECTED WORD

//Repeat until the RANDOM WORD is empty

到目前为止，这是我的代码：

导入UIKit

//this is my array/word bank
var words = ["Apple", "Orange", "Pear"]

//this selects a random word in the array
var selectedWord = words[Int(arc4random_uniform(UInt32(words.count)))]

//this counts the number of characters in the string
var length = (countElements(selectedWord))

//this randomly selects a position within the string
var position = Int(arc4random_uniform(UInt32(length)))

//this creates a new string consiting of the letter found in the position from the previous line of code
var subString = selectedWord[advance(selectedWord.startIndex, position)]

我的问题是我无法弄清楚如何从所选单词中删除所选字符。如果可以的话，我只需创建一个循环，然后重复上面的过程直到原始单词为空

Answer 1

Swift 5或更高版本

extension RangeReplaceableCollection  { 
    /// Returns a new collection containing this collection shuffled
    var shuffled: Self {
        var elements = self
        return elements.shuffleInPlace()
    }
    /// Shuffles this collection in place
    @discardableResult
    mutating func shuffleInPlace() -> Self  {
        indices.forEach {
            let subSequence = self[$0...$0]
            let index = indices.randomElement()!
            replaceSubrange($0...$0, with: self[index...index])
            replaceSubrange(index...index, with: subSequence)
        }
        return self
    }
    func choose(_ n: Int) -> SubSequence { return shuffled.prefix(n) }
}

---

let words = ["python", "jumble", "easy", "difficult", "answer", "xylophone"]

let randomWordShuffled = words.randomElement()?.shuffled ?? "" // "jmeblu"

Answer 2

您希望随机播放String。

的内容

最简单的方法是：

1. 将字符串转换为数组：var a = Array(selectedWord)
2. 使用this answer中的信息对该阵列进行随机播放
3. 将数组转换回字符串：let shuffledString = String(a)

因此，如果您选择变异的随机播放算法：

extension Array {
    mutating func shuffle() {
        for i in 0..<(count - 1) {
            let j = Int(arc4random_uniform(UInt32(count - i))) + i
            guard i != j else { continue}
            swap(&self[i], &self[j])
        }
    }
}

let selectedWord = "Apple"

var a = Array(selectedWord)
a.shuffle()
let shuffledWord = String(a)
// shuffledWord = “pAelp” or similar

Answer 3

func scramble(word: String) -> String {
    var chars = Array(word.characters)
    var result = ""

    while chars.count > 0 {
        let index = Int(arc4random_uniform(UInt32(chars.count - 1)))
        chars[index].writeTo(&result)
        chars.removeAtIndex(index)
    }

    return result
}

Character结构，通过上述代码中的word.characters，具有writeTo任意OutputStreamType的功能，包括String个对象。因此，在对结果字符串中随机选择Character后，只需将其删除，然后继续循环，直到不再有字符为止。

Answer 4

你可以使用许多不同的算法来改变一个单词，但这里有一个我用同样的方式编写的算法/使用与当前算法类似的代码，它重复选择并删除一个随机字符要添加到新字符串的原始字符串：

//this is my array/word bank
var words = ["Apple", "Orange", "Pear"]

//this selects a random word in the array
var selectedWord = words[Int(arc4random_uniform(UInt32(words.count)))]

// The string that will eventually hold the shuffled word
var shuffledWord:String = ""

// Loop until the "selectedWord" string is empty  
while countElements(selectedWord) > 0 {

    // Get the random index
    var length = countElements(selectedWord)
    var position = Int(arc4random_uniform(UInt32(length)))

    // Get the character at that random index
    var subString = selectedWord[advance(selectedWord.startIndex, position)]
    // Add the character to the shuffledWord string
    shuffledWord.append(subString)
    // Remove the character from the original selectedWord string
    selectedWord.removeAtIndex(advance(selectedWord.startIndex, position))
}

println("shuffled word: \(shuffledWord)")

Answer 5

这是一个解决方案：

var myString = "abcdefg"
let shuffledString = String(Array(myString).shuffled())

说明：

1. 将 myString 转换为字符数组
2. 打乱数组
3. 将数组转换回字符串