天真的方法总结了一系列对象？

发布于 2025-02-12 08:19:00 字数 110 浏览 1 评论 0原文

我面临着一个挑战，需要通过对象键总结一系列对象。我找到了一个解决方案，但是我无法摆脱这种感觉，我的方法很幼稚：

const objArr = [
    { id: 1, val: "

原文

I faced a challenge where I needed to summarize an array of objects by the object's keys. I found a solution, but I can't shake off the feeling, that my approach is pretty naive:

const objArr = [
    { id: 1, val: "????" },
    { id: 1, val: "????" },
    { id: 1, val: "????" },
    { id: 2, val: "????" },
    { id: 2, val: "????" },
    { id: 2, val: "????" },
];

let tempArr = [];
let uniqueIdArr = [];
let sortedArr = [];

objArr.forEach((obj) => {
    tempArr.push(obj.id);
    uniqueIdArr = [...new Set(tempArr)];
});

uniqueIdArr.forEach((uniqueId) => {
    let arr = [];
    objArr.forEach((obj) => {
        if (obj.id == uniqueId) {
            arr.push(obj.val);
        }
    });
    sortedArr.push({
        id: uniqueId,
        vals: arr,
    });
});

console.log(sortedArr);
// Output: [{ id: 1, vals: [ '????', '????', '????' ] }, { id: 2, vals: [ '????', '????', '????' ] }]

Maybe there is something I don't know about JavaScript's array methods yet? Is this approach totally wrong? Is there another way, so that I could reduce the code and make it more elegant?

So many questions...

Any hint or explanation would be much appreciated. ????

Thanks in advance

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十级心震 2025-02-19 08:19:00

您可以使用array.prototype.reduce使您的代码位短：

const objArr = [

    { id: 1, val: "

you can use Array.prototype.reduce to make your code bit shorter:

const objArr = [
    { id: 1, val: "????" },
    { id: 1, val: "????" },
    { id: 1, val: "????" },
    { id: 2, val: "????" },
    { id: 2, val: "????" },
    { id: 2, val: "????" },
];

let result = objArr.reduce((acc,e) => {
    let idx = acc.findIndex(s => s.id === e.id)
    if(idx > -1){
        acc[idx].vals.push(e.val)
    }
    else{
        acc.push({id:e.id,vals:[e.val]})
    }
    return acc
},[])


console.log(result)

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我不是你的备胎 2025-02-19 08:19:00

您的想法是好的和明确的，但远非最佳。

const objArr = [

    { id: 1, val: "

Your ideas are good and explicit, but far from being optimal.

const objArr = [
    { id: 1, val: "????" },
    { id: 1, val: "????" },
    { id: 1, val: "????" },
    { id: 2, val: "????" },
    { id: 2, val: "????" },
    { id: 2, val: "????" },
];
const idValMap = new Map();

objArr.forEach(o=>{
   let vals = idValMap.get(o.id);
   if(!vals){
       vals = [];
       idValMap.set(o.id,vals);
   }
   vals.push(o.val);
});

console.log(Array.from(idValMap.entries()));

You can do most of it in just one loop. Take the key, check if you saw it already, if not initialize. That's it

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一紙繁鸢 2025-02-19 08:19:00

该解决方案可能不是好多了，但它确实使用较少的代码：

const objArr = [

    { id: 1, val: "

This solution probably isn't much better but it is does use less code:

const objArr = [
    { id: 1, val: "????" },
    { id: 1, val: "????" },
    { id: 1, val: "????" },
    { id: 2, val: "????" },
    { id: 2, val: "????" },
    { id: 2, val: "????" },
];

let sortedArr = [];

objArr.forEach((item) => {
    const exists = sortedArr.filter(i => i.id === item.id).length; // Check to see if we've already added an item with this ID
    if (!exists) {
        const matches = objArr.filter(i => i.id == item.id); // get all items with this ID

        sortedArr.push({
            id: item.id,
            vals: matches.map(m => m.val) // We only care about the val property
        });
    }
});

See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map and https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter for informationa bout .map() and .filter() respectively

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~没有更多了~