javascript - 如何按照一定的规则设置数组的元素

Question

假设我们有这样的数组:

const words = ['luigi', 'Bar', 'Test', 'zac1', 'Alf0'];

现在我想按字母顺序对这个数组进行排序:

words.sort((a, b) => a.localeCompare(b));

假设我们有一组 super 词。此词具有高优先级，应位于“词列表”的顶部。

const superWords = ["zac1", "Test"]

因此 words 数组的期望结果将是:

const desiredResult = ["Test", "zac1","Alf0", "Bar", "luigi"]

我该怎么做？

Answer 1

您可以将 superWords 转换为 Set O(1) 查找时间使用 has而不是 O(n) 使用 includes当 superWords 是 Array 时(其中 n 是 superWords 中的单词数):

const words = ['luigi', 'Bar', 'Test', 'zac1', 'Alf0'];
const superWords = ['zac1', 'Test'];
const superWordsSet = new Set(superWords); // This is O(n) but you only need to do this once.
words.sort((a, b) => {
    if (superWordsSet.has(a) && !superWordsSet.has(b)) {
        return -1;
    } else if (!superWordsSet.has(a) && superWordsSet.has(b)) {
        return 1;
    }
    return a.localeCompare(b);
});
console.log(words);

Performance

The Set has method checks if a value is in a Set object, using an approach that is, on average, quicker than testing most of the elements that have previously been added to the Set object. In particular, it is, on average, faster than the Array.prototype.includes method when an Array object has a length equal to a Set object's size.