Javascript映射和合并对象数组[关闭]答案

【问题标题】：Javascript map and conslidate object array [closed]Javascript映射和合并对象数组[关闭]
【发布时间】：2022-01-23 22:22:34
【问题描述】：

我正在使用一个对象数组，例如：

const data = [
{"Bucket":1, "Currency": "USD", "xt":8465, "yt":3545}
{"Bucket":2, "Currency": "EUR", "xt":63, "yt":71}
{"Bucket":3, "Currency": "JPY", "xt":48, "yt":56}
{"Bucket":4, "Currency": "CAD", "xt":89}
{"Bucket":1, "xt":9256, "yt":3865}
{"Bucket":2, "xt":63, "yt":74}
{"Bucket":3, "xt":46, "yt":57}
{"Bucket":4, "xt":90}
]

很难将上面的数组合并成这样的：

const data = [
{"Bucket":1, "Currency": "USD", "xt":{8465,9256}, "yt":{3545,3865}}
{"Bucket":2, "Currency": "EUR", "xt":{63,63}, "yt":{71,74}}
{"Bucket":3, "Currency": "JPY", "xt":{48,46}, "yt":{56,57}}
{"Bucket":4, "Currency": "CAD", "xt":{89,90}}
]

【问题讨论】：

请分享您的尝试？带来更好的响应
"xt" : {8465, 9256} 是不可能的。你必须有一个 key-value 对象对，或者将它们作为数组
对不起，我的意思是 "xt" : { "Current" : 8465, "Compare": 9256}

标签： javascript arrays typescript

【解决方案1】：

您可以执行以下操作：

function combineXtYt(data) {
  const result = [];

  for(let i=0, j=0; i<data.length; i++) {
    const isPresentIndex = result.findIndex((needle) => needle.Bucket === data[i].Bucket);
    if(isPresentIndex >= 0) {
      result[isPresentIndex].xt = { Current: result[isPresentIndex].xt, Compare: data[i].xt}
      result[isPresentIndex].yt = { Current: result[isPresentIndex].yt, Compare: data[i].yt}
    } else {
      result[j++] = {...data[i]};
    }
  }
 return result;
}


const data = [
{"Bucket":1, "Currency": "USD", "xt":8465, "yt":3545},
{"Bucket":2, "Currency": "EUR", "xt":63, "yt":71},
{"Bucket":3, "Currency": "JPY", "xt":48, "yt":56},
{"Bucket":4, "Currency": "CAD", "xt":89, "yt":97},
{"Bucket":1, "xt":9256, "yt":3865},
{"Bucket":2, "xt":63, "yt":74},
{"Bucket":3, "xt":46, "yt":57},
{"Bucket":4, "xt":90, "yt":95}
]

console.log(combineXtYt(data))

注意：我相信，这可以针对时间复杂度进行进一步优化，但这应该可以帮助您入门。

【讨论】：

【解决方案2】：

您可以使用reduce 和find 方法来做到这一点，如下所示：

const data = [
{"Bucket":1, "Currency": "USD", "xt":8465, "yt":3545},
{"Bucket":2, "Currency": "EUR", "xt":63, "yt":71},
{"Bucket":3, "Currency": "JPY", "xt":48, "yt":56},
{"Bucket":4, "Currency": "CAD", "xt":89, "yt":97},
{"Bucket":1, "xt":9256, "yt":3865},
{"Bucket":2, "xt":63, "yt":74},
{"Bucket":3, "xt":46, "yt":57},
{"Bucket":4, "xt":90, "yt":95},
];

const result = data.reduce((acc, item) => {
  const bucket = acc.find(v => v.Bucket == item.Bucket);
  if (bucket) { //Bucket exist, just update xt.compare and yt.compare
    bucket.xt.compare = item.xt;
    bucket.yt.compare = item.yt;
  } else {
    acc.push({...item, xt: {current: item.xt}, yt: {current:item.yt} })
  }
  return acc;
}, []);
console.log(result);

【讨论】：