如何多次打乱 JavaScript 中的数组

Question

我一直在阅读有关在 JavaScript 中对数组执行洗牌的最佳方法，并且遇到了 Fisher-Yates 模型（在 this article and in this article 中）。我已经尝试使用文章中指向的两个示例函数，但是当我想多次打乱数组并将不同的结果分配给两个不同的变量时，它们最终会完全相同。

    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 playerHand returns:

["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"]

和 computerHand returns:

["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"]

这可能非常简单，但我很难过。我认为再次调用该函数会 return 不同的结果。

Answer 1

您的函数在那里随机播放数组 "in-place" - 也就是说，它正在更改数组而不是创建新数组。

因为在第二次调用中它是同一个数组，所以你是 "loosing" 第一个洗牌结果。

要解决此问题，请创建数组的克隆：

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

如何多次打乱 JavaScript 中的数组

How to shuffle an array in JavaScript more than once

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