【问题标题】:How to group array of objects by common property and put other properties together如何按公共属性对对象数组进行分组并将其他属性放在一起
【发布时间】:2021-08-21 12:50:12
【问题描述】:

我有一个这样的对象数组

const statuses = [
  {time: '21/1/1990', 'Status.sold': 8848},
  {time: '21/1/1990', 'Status.reserved': 8804},
  {time: '21/1/1991', 'Status.reserved': 8756},
  {time: '21/1/1991', 'Status.sold': 8732},
  {time: '21/1/1992', 'Status.killed': 8691},
  {time: '21/1/1992', 'Status.sold': 8620},
  {time: '21/1/1993', 'Status.held': 8511},
  {time: '21/1/1993', 'Status.killed': 8511},
  {time: '21/1/1994', 'Status.sold': 8498},
];

我想要实现的是将所有Status. 属性放在一起并按time 属性分组,这对所有对象都是通用的。所以最终的结果会是这样的

const statuses = [
  {time: '21/1/1990', sold: 8848, killed: 0, reserved: 8804, held: 0},
  {time: '21/1/1991', sold: 8732, killed: 0, reserved: 8756, held: 0},
  {time: '21/1/1992', sold: 8620, killed: 8691, reserved: 0, held: 0},
  {time: '21/1/1993', sold: 0, killed: 8511, reserved: 0, held: 8511},
  {time: '21/1/1994', sold: 8498, killed: 0, reserved: 0, held: 0},
];

我尝试过类似的方法

const result = statuses.map((obj) => {
   return { ...obj, 
      sold: obj['Status.sold'] ? obj['Status.sold'] : 0,
      reserved: obj['Status.reserved'] ? obj['Status.reserved'] : 0,
      killed: obj['Status.killed'] ? obj['Status.killed'] : 0,
      held: obj['Status.held'] ? obj['Status.held'] : 0
   };
});

但我不确定如何按time 对它们进行分组。如何将reduce方法与此代码结合使用?提前致谢!

【问题讨论】:

标签: javascript arrays object ecmascript-6 reduce


【解决方案1】:

您可以将对象按time 分组。

const
    statuses = [{ time: '21/1/1990', 'Status.sold': 8848 }, { time: '21/1/1990', 'Status.reserved': 8804 }, { time: '21/1/1991', 'Status.reserved': 8756 }, { time: '21/1/1991', 'Status.sold': 8732 }, { time: '21/1/1992', 'Status.killed': 8691 }, { time: '21/1/1992', 'Status.sold': 8620 }, { time: '21/1/1993', 'Status.held': 8511 }, { time: '21/1/1993', 'Status.killed': 8511 }, { time: '21/1/1994', 'Status.sold': 8498 }],
    result = Object.values(statuses.reduce((r, { time, ...o }) => {
        r[time] ??= { time, sold: 0, killed: 0, reserved: 0, held: 0 };
        Object.entries(o).forEach(([k, v]) => r[time][k.slice(7)] += v);
        return r;
    }, {}));

console.log(result);
.as-console-wrapper { max-height: 100% !important; top: 0; }

【讨论】:

  • 你能解释一下为什么我们需要k.slice(7) 吗?谢谢!
  • 这是为了仅从'Status.sold' 中获取单词'killed',例如。也许您想要完整的字符串或使用拆分值的嵌套方法...?
【解决方案2】:

试试这个:

const statuses = [
  {time: '21/1/1990', 'Status.sold': 8848},
  {time: '21/1/1990', 'Status.reserved': 8804},
  {time: '21/1/1991', 'Status.reserved': 8756},
  {time: '21/1/1991', 'Status.sold': 8732},
  {time: '21/1/1992', 'Status.killed': 8691},
  {time: '21/1/1992', 'Status.sold': 8620},
  {time: '21/1/1993', 'Status.held': 8511},
  {time: '21/1/1993', 'Status.killed': 8511},
  {time: '21/1/1994', 'Status.sold': 8498},
];

const result = [];

let obj = {};
for (let i = 0; i < statuses.length; i++) {
  const status = statuses[i];
  if (status.time != obj.time) {
    if (i != 0) result.push(obj); 
    obj = {
      time: status.time,
      sold: 0,
      reserved: 0,
      killed: 0,
      held: 0,
    }
  }
  if (status['Status.sold']) obj.sold += status['Status.sold'];
  if (status['Status.reserved']) obj.reserved += status['Status.reserved'];
  if (status['Status.killed']) obj.killed += status['Status.killed'];
  if (status['Status.held']) obj.held += status['Status.held'];
}
result.push(obj);
console.log(result);

【讨论】:

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