访问数组中的所有其他项目 - JavaScript
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Access every other item in an array - JavaScript
提问by Rafill
Is it possible for me to access every other item in an array? So basically, all items in positions 0, 2, 4, 6 etc.
我是否可以访问数组中的所有其他项目？所以基本上，位置 0、2、4、6 等中的所有项目。
Here's my code if it helps:
如果有帮助，这是我的代码：
function pushToHash(key, value) {
for (var t = 0; t < value.length; t++) {
MQHash[key[t]] = value.slice(0, lineLength[t]);
}
}
So, I need to get every other value of lineLength. I only want this for lineLength, not key. I was thinking of doing a modulus, but wasn't sure how I'd implement it. Any ideas?
所以，我需要获得lineLength. 我只想要这个lineLength，不是key。我正在考虑做一个模数，但不确定如何实现它。有任何想法吗？
Thanks in advance!
提前致谢！
采纳答案by T.J. Crowder
If you just want this with lineLengthand not with key, then add a second variable and use +=when incrementing:
如果您只想要 withlineLength而不是 with key，则添加第二个变量并+=在递增时使用：
function pushToHash(key, value) {
for (var t = 0, x = 0; t < value.length; t++, x += 2) {
MQHash[key[t]] = value.slice(0, lineLength[x]);
}
}
(The power of the comma operator...)
（逗号运算符的威力……）
回答by dannymac
You can use the index (second parameter) in the array filter method like this:
您可以在数组过滤器方法中使用索引（第二个参数），如下所示：
let arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
// filter out all elements that are located at an even index in the array.
let x = arr.filter((element, index) => {
return index % 2 === 0;
})
console.log(x)
// [1, 3, 5, 7, 9]
