如何获取数组的每个第三个元素 [英] How to take every 3rd element of an array

问题描述

我有一个数组，只想将每三个元素作为一个新数组返回(从0开始).

I have an array, and want to return only every third element as a new array (starting at 0).

例如:

let arr = [1, 2, 3, 4, 5, 6, 7, 8, 9];
let newArr = [1, 4, 7];

这是我目前正在这样做的方式:

This is the way I am currently doing this:

let newArr = [];
for(let x = 0; x < arr.length; x += 3) {
   newArr.push(arr[x]);
}
return newArr;

有没有办法用arr.map做到这一点?有没有更简单的方法可以做到这一点?

Is there a way to do this with arr.map? Is there just an easier way to do this?

推荐答案

您也可以使用

You can alternatively do it with a filter,

let newArr = arr.filter((_,i) => i % 3 == 0); 

但是请记住，在某些情况下，使用基本的for循环要比其他方法更有效率.

But remember, using basic for loop is bit more efficient than others in some contexts.

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