Question

我有一个包含num和sum

的对象数组

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    <div class="jumbotron" style="width:100%">
        <h1>
            ConfigTool Web Interface
        </h1>
        <p>
            Edit the config variables here and click save.
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        <label class="col-2">Name:</label>
        <input class="form-control col-10" type="text" />
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</div>

我想要的是：

[
   {num: 1, sum: 10},
   {num: 1, sum: 2},
   {num: 1, sum: 3},
   {num: 2, sum: 1},
   {num: 2, sum: 40},
   {num: 2, sum: 100},
   {num: 3, sum: 0},
   {num: 4, sum: 0},
]

非常感谢任何帮助

Answer 1

一个选项是reduce进入由num s索引的对象，然后将map该对象转换为数组：

＆＃13;

const input=[{num:1,sum:10},{num:1,sum:2},{num:1,sum:3},{num:2,sum:1},{num:2,sum:40},{num:2,sum:100},{num:3,sum:0},{num:4,sum:0},]
const outputObj = input.reduce((a, { num, sum }) => {
  if (!a[num]) a[num] = { count: 0, totalSum: 0 };
  a[num].count++;
  a[num].totalSum += sum;
  return a;
}, {});
const output = Object.entries(outputObj)
  .map(([key, val]) => ({ [key] : val }));
console.log(output);

＆＃13;

Answer 2

您可以使用reduce方法对数组进行分组，然后使用其他reduce方法，以便为每个键找到count和totalSum属性。

let arr = [ {num: 1, sum: 10}, {num: 1, sum: 2}, {num: 1, sum: 3}, {num: 2, sum: 1}, {num: 2, sum: 40}, {num: 2, sum: 100}, {num: 3, sum: 0}, {num: 4, sum: 0}, ]

var groupBy = function(arr, key) {
  return arr.reduce(function(acc, x) {
    (acc[x[key]] = acc[x[key]] || []).push(x);
    return acc;
  }, {});
};

let grouped = groupBy(arr, 'num');

let result = Object.keys(grouped).reduce(function(acc, key){
  let obj ={ [key] :  {count : grouped[key].length, totalSum: grouped[key].map(a => a.sum).reduce((a,b) => a + b)}}
  acc.push(obj)
  return acc;
},[]);
console.log(result);

Javascript从给定数组创建新数组

2 个答案: