在 JavaScript 中获取数组的最后 N 个元素

获取数组的最后 N 个元素

Get the last N elements of an Array in JavaScript

使用该Array.slice()方法获取数组的最后 N 个元素，例如
const last3 = arr.slice(-3).

该Array.slice()方法将返回一个新数组，其中包含原始数组的最后 N 个元素。

const arr = ['a', 'b', 'c', 'd', 'e'];

const last3 = arr.slice(-3); // 👉️ ['c', 'd', 'e']
console.log(last3);

const last2 = arr.slice(-2); // 👉️ ['d', 'e']
console.log(last2);

我们传递给
Array.slice()
方法的唯一参数是起始索引。

这与将参数传递array.length - 3给slice()
方法相同。

const arr = ['a', 'b', 'c', 'd', 'e'];

const last3 = arr.slice(-3);
console.log(last3); // 👉️ ['c', 'd', 'e']

const last3Again = arr.slice(arr.length - 3);
console.log(last3Again); // 👉️ ['c', 'd', 'e']

Either way, we tell the slice() method to copy the last 3 elements of the
array and place them in a new array.

Even if we try to get more elements than the array contains, Array.slice()
won’t throw an error. Instead, it returns a new array with all elements of the
original array.

const arr = ['a', 'b', 'c'];

const last100 = arr.slice(-100);
console.log(last100); // 👉️ ['a', 'b', 'c']

We tried to get the last 100 elements of an array that only contains 3
elements.

In this case, all elements of the original array get copied to the new array.