如何在JavaScript中多次洗牌数组

Question

我一直在阅读在JavaScript中对数组执行洗牌的最佳方法，并且遇到了Fisher-Yates模型(在这篇文章和这篇文章中)。我尝试使用文章中提到的两个示例函数，但是当我想要对数组进行多次洗牌并将不同的结果赋给两个不同的变量时，它们的结果完全相同。

    function shuffle(array) {
    var i = 0,
        j = 0,
        temp = null

    for (i = array.length - 1; i > 0; i -= 1) {
        j = Math.floor(Math.random() * (i + 1))
        temp = array[i]
        array[i] = array[j]
        array[j] = temp
    }
    return array;
}

var deck = ["bat", "black-cat", "blood", "bone", "brain", "broom", "candle", "candy", "castle", "cauldrom", "coffin", "costume", "death", "devil", "fish-bone", "full-moon", "ghost", "grave", "grave-yard", "half-moon", "horror", "lantern", "magic", "monster", "owl", "pumpkin", "skull", "spider", "spider-web", "tree", "tree-2", "witch", "witch-hat", "zombie-1", "zombie-2"];



var playerHand = shuffle(deck);
var computerHand = shuffle(deck);

console.log(playerHand);
console.log(computerHand);

在控制台中，playerHand返回：

["castle", "costume", "coffin", "candy", "blood", "death", "horror", "skull", "spider", "broom", "owl", "tree", "spider-web", "pumpkin", "grave", "devil", "brain", "ghost", "witch-hat", "magic", "bat", "black-cat", "full-moon", "tree-2", "cauldrom", "bone", "grave-yard", "half-moon", "zombie-1", "lantern", "monster", "zombie-2", "candle", "fish-bone", "witch"]

computerHand返回：

["castle", "costume", "coffin", "candy", "blood", "death", "horror", "skull", "spider", "broom", "owl", "tree", "spider-web", "pumpkin", "grave", "devil", "brain", "ghost", "witch-hat", "magic", "bat", "black-cat", "full-moon", "tree-2", "cauldrom", "bone", "grave-yard", "half-moon", "zombie-1", "lantern", "monster", "zombie-2", "candle", "fish-bone", "witch"]

这可能很简单，但我很困惑。我认为再次调用函数会返回不同的结果。

Answer 1

您的函数在“就地”数组中进行洗牌，也就是说，它正在更改数组，而不是创建新的数组。

因为它在第二个调用中是相同的数组，所以您正在“失去”第一个洗牌结果。

要解决这个问题，创建一个数组的克隆：

var playerHand = shuffle(deck.slice());
var computerHand = shuffle(deck.slice());