在 JavaScript 中如何将数组拆分为数组对？
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How do you split an array into array pairs in JavaScript?
提问by Tormod Smith
I want to split an array into pairs of arrays.
我想将一个数组拆分为成对的数组。
var arr = [2, 3, 4, 5, 6, 4, 3, 5, 5]
would be
将是
var newarr = [
[2, 3],
[4, 5],
[6, 4],
[3, 5],
[5]
]
回答by Vbyec
回答by ChadF
There's no pre-baked function to do that, but here's a simple solution:
没有预先烘焙的功能可以做到这一点，但这里有一个简单的解决方案：
var splitPairs = function(arr) {
var pairs = [];
for (var i=0 ; i<arr.length ; i+=2) {
if (arr[i+1] !== undefined) {
pairs.push ([arr[i], arr[i+1]]);
} else {
pairs.push ([arr[i]]);
}
}
return pairs;
};
回答by vinniecent
Lodash has a method for this: https://lodash.com/docs/4.17.10#chunk
Lodash 有一个方法：https://lodash.com/docs/4.17.10#chunk
_.chunk([2,3,4,5,6,4,3,5,5], 2);
// => [[2,3],[4,5],[6,4],[3,5],[5]]
_.chunk([2,3,4,5,6,4,3,5,5], 2);
// => [[2,3],[4,5],[6,4],[3,5],[5]]
回答by Matt Lacey
Yet another that's a bit of a mish-mash of the already-posted answers. Adding it because having read the answers I still felt things could be a little easier to read:
另一个是已经发布的答案的大杂烩。添加它是因为在阅读了答案后，我仍然觉得事情可能更容易阅读：
var groups = [];
for(var i = 0; i < arr.length; i += 2)
{
groups.push(arr.slice(i, i + 2));
}
回答by Jason Cust
A slightly different approach than using a forloop for comparison. To avoid modifying the original array slicemakes a shallow copy since JS passes objects by reference.
与使用for循环进行比较的方法略有不同。为了避免修改原始数组slice，因为 JS 通过引用传递对象，所以进行浅拷贝。
function pairArray(a) {
var temp = a.slice();
var arr = [];
while (temp.length) {
arr.push(temp.splice(0,2));
}
return arr;
}
var array = [2,3,4,5,6,4,3,5,5];
var newArr = pairArray(array);
function pairArray(a) {
var temp = a.slice();
var arr = [];
while (temp.length) {
arr.push(temp.splice(0,2));
}
return arr;
}
document.write('<pre>' + JSON.stringify(newArr) + '</pre>');回答by Mark T
I would use lodashfor situations like this.
我会在这种情况下使用lodash。
Here is a solution using _.reduce:
这是使用的解决方案_.reduce：
var newArr = _(arr).reduce(function(result, value, index) {
if (index % 2 === 0)
result.push(arr.slice(index, index + 2));
return result;
}, []);
var arr = [2,3,4,5,6,4,3,5,5];
var newArr = _(arr).reduce(function(result, value, index) {
if (index % 2 === 0)
result.push(arr.slice(index, index + 2));
return result;
}, []);
document.write(JSON.stringify(newArr)); // [[2,3],[4,5],[6,4],[3,5],[5]]<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/3.10.0/lodash.min.js"></script>回答by alden
Here's another solution using lodash helpers:
这是使用 lodash 助手的另一个解决方案：
function toPairs(array) {
const evens = array.filter((o, i) => i % 2);
const odds = array.filter((o, i) => !(i % 2));
return _.zipWith(evens, odds, (e, o) => e ? [o, e] : [o]);
}
console.log(toPairs([2,3,4,5,6,4,3,5,5]));<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.13.1/lodash.min.js"></script>回答by doeke
It's possible to group an array into pairs/chunks in one line without libraries:
可以在没有库的情况下在一行中将数组分组为成对/块：
function chunks(arr, size = 2) {
return arr.map((x, i) => i % size == 0 && arr.slice(i, i + size)).filter(x => x)
}
console.log(chunks([1, 2, 3, 4, 5, 6, 7])) // -> [[1, 2], [3, 4], [5, 6], [7]]回答by Simon Buchan
There is now the flexible Array#flatMap(value, index, array):
现在有灵活的Array#flatMap(value, index, array)：
const pairs = arr.flatMap((_, i, a) => i % 2 ? [] : [a.slice(i, i + 2)]);
And the possibly more efficient, but goofy looking Array.from(source, mapfn?):
并且可能更有效，但看起来很傻Array.from(source, mapfn?)：
const pairs = Array.from({ length: arr.length / 2 }, (_, i) => arr.slice(i * 2, i * 2 + 2))
回答by chirag
const items = [1, 2, 3, 4, 5];
const createBucket = (bucketItems, bucketSize) => buckets => {
return bucketItems.length === 0 ? buckets : [...buckets, bucketItems.splice(0, bucketSize)];
};
const bucketWithItems = items.reduce(createBucket([...items], 4), []);