对象数组按特定键将它们分组

Question

我有以下数组

const arr = [{
  agrupacion: "Total país",
  valor: "81.8",
  year: 2015
}, {
  agrupacion: "Total país",
  valor: "86.4",
  year: 2016
}, {
  agrupacion: "Total país",
  valor: "67.3",
  year: 2017
}, {
  agrupacion: "Total país",
  valor: "70.8",
  year: 2018
}, {
  agrupacion: "Total país",
  valor: "67.6",
  year: 2019
}, {
  agrupacion: "Oriental",
  valor: "78.6",
  year: 2015
}, {
  agrupacion: "Oriental",
  valor: "83.1",
  year: 2016
}, {
  agrupacion: "Oriental",
  valor: "65.6",
  year: 2017
}, {
  agrupacion: "Oriental",
  valor: "68.1",
  year: 2018
}, {
  agrupacion: "Oriental",
  valor: "63.7",
  year: 2019
}, {
  agrupacion: "Occidental",
  valor: "177.3",
  year: 2015
}, {
  agrupacion: "Occidental",
  valor: "182.9",
  year: 2016
}, {
  agrupacion: "Occidental",
  valor: "114.3",
  year: 2017
}, {
  agrupacion: "Occidental",
  valor: "144.5",
  year: 2018
}, {
  agrupacion: "Occidental",
  valor: "169.9",
  year: 2019
}, {
  agrupacion: "Urbano",
  valor: "79.6",
  year: 2015
}, {
  agrupacion: "Urbano",
  valor: "92.5",
  year: 2016
}, {
  agrupacion: "Urbano",
  valor: "62.1",
  year: 2017
}, {
  agrupacion: "Urbano",
  valor: "82.2",
  year: 2018
}, {
  agrupacion: "Urbano",
  valor: "80.6",
  year: 2019
}, {
  agrupacion: "Rural",
  valor: "86.5",
  year: 2015
}, {
  agrupacion: "Rural",
  valor: "63.7",
  year: 2016
}, {
  agrupacion: "Rural",
  valor: "87.2",
  year: 2017
}, {
  agrupacion: "Rural",
  valor: "45.7",
  year: 2018
}, {
  agrupacion: "Rural",
  valor: "38.9",
  year: 2019
}];

我用这个方法实现了我想要的：

const groups = new Map(arr.map(({agrupacion}) => [agrupacion, { agrupacion }]));
for (const {agrupacion, valor, year} of arr) {
    groups.get(agrupacion)["col" + year] = +valor;
}

const result = [...groups.values()];

输出是 (console.log(result )):

[{
  agrupacion: "Total país",
  col2015: 81.8,
  col2016: 86.4,
  col2017: 67.3,
  col2018: 70.8,
  col2019: 67.6
}, {
  agrupacion: "Oriental",
  col2015: 78.6,
  col2016: 83.1,
  col2017: 65.6,
  col2018: 68.1,
  col2019: 63.7
}, {
  agrupacion: "Occidental",
  col2015: 177.3,
  col2016: 182.9,
  col2017: 114.3,
  col2018: 144.5,
  col2019: 169.9
}, {
  agrupacion: "Urbano",
  col2015: 79.6,
  col2016: 92.5,
  col2017: 62.1,
  col2018: 82.2,
  col2019: 80.6
}, {
  agrupacion: "Rural",
  col2015: 86.5,
  col2016: 63.7,
  col2017: 87.2,
  col2018: 45.7,
  col2019: 38.9
}];

该输出是我需要的格式，但是当我将具有相同“agrupacion”值的其他数据添加到我的 arr 数组时，例如我将其添加到我的 arr 数组的末尾时，问题就来了

,{
  agrupacion: "Total país",
  valor: "151",
  year: 2015
}, {
  agrupacion: "Total país",
  valor: "184",
  year: 2016
}, {
  agrupacion: "Total país",
  valor: "165",
  year: 2017
}, {
  agrupacion: "Total país",
  valor: "147",
  year: 2018
}, {
  agrupacion: "Total país",
  valor: "190",
  year: 2019
}

这是我需要的：

[{
  agrupacion: "Total país",
  col2015: 81.8,
  col2016: 86.4,
  col2017: 67.3,
  col2018: 70.8,
  col2019: 67.6
}, {
  agrupacion: "Oriental",
  col2015: 78.6,
  col2016: 83.1,
  col2017: 65.6,
  col2018: 68.1,
  col2019: 63.7
}, {
  agrupacion: "Occidental",
  col2015: 177.3,
  col2016: 182.9,
  col2017: 114.3,
  col2018: 144.5,
  col2019: 169.9
}, {
  agrupacion: "Urbano",
  col2015: 79.6,
  col2016: 92.5,
  col2017: 62.1,
  col2018: 82.2,
  col2019: 80.6
}, {
  agrupacion: "Rural",
  col2015: 86.5,
  col2016: 63.7,
  col2017: 87.2,
  col2018: 45.7,
  col2019: 38.9
},{
  agrupacion: "Total país",
  col2015: 151,
  col2016: 184,
  col2017: 165,
  col2018: 147,
  col2019: 190
}];

这是我尝试得到的结果：

[{
  agrupacion: "Total país",
  col2015: 151,
  col2016: 184,
  col2017: 165,
  col2018: 147,
  col2019: 190
}, {
  agrupacion: "Oriental",
  col2015: 78.6,
  col2016: 83.1,
  col2017: 65.6,
  col2018: 68.1,
  col2019: 63.7
}, {
  agrupacion: "Occidental",
  col2015: 177.3,
  col2016: 182.9,
  col2017: 114.3,
  col2018: 144.5,
  col2019: 169.9
}, {
  agrupacion: "Urbano",
  col2015: 79.6,
  col2016: 92.5,
  col2017: 62.1,
  col2018: 82.2,
  col2019: 80.6
}, {
  agrupacion: "Rural",
  col2015: 86.5,
  col2016: 63.7,
  col2017: 87.2,
  col2018: 45.7,
  col2019: 38.9
}]

显然它覆盖了第一个“Total país”中的所有值，而不是用我添加的新值重复那个agrupacion

Answer 1

为每个函数试试这个：

 let arrayBuild = []
      let results = []
      let currentAgrupacion = ''
      let element = {}
      
      arr.forEach(elem => {
        if(currentAgrupacion !== elem.agrupacion) {
          if(currentAgrupacion !== '') {
            results.push(element)
          }
          currentAgrupacion = elem.agrupacion
          element = {
            agrupacion: elem.agrupacion
          }
      element["col"+elem.year] = parseFloat(elem.valor)
    }
    else {
      element["col"+elem.year] = parseFloat(elem.valor)
    }
  })
  results.push(element)

  console.log(results)

Answer 2

将数组缩减为一个对象，其中键对应于 agrupacion，值对应于一个对象数组。这个数组的长度是根据特定 agrupacion.

一年出现的次数决定的

所以，下面的数组：

[
  { agrupacion: "Total país", valor: "81.8", year: 2015 },
  { agrupacion: "Total país", valor: "86.4", year: 2016 },
  { agrupacion: "Total país", valor: "67.3", year: 2015 },
  { agrupacion: "Oriental", valor: "78.6", year: 2015 },
]

被缩减为以下对象：

{
  "Total país": [
    { agrupacion: "Total país", col2015: 81.8, col2016: 86.4 },
    { agrupacion: "Total país", col2015: 67.3 },
  ],
  Oriental: [{ agrupacion: "Oriental", col2015: 78.6 }],
}

最后我们得到了这个对象的值并将它展平到想要的结果。

const arr = [
  { agrupacion: "Total país", valor: "81.8", year: 2015 },
  { agrupacion: "Total país", valor: "86.4", year: 2016 },
  { agrupacion: "Total país", valor: "67.3", year: 2017 },
  { agrupacion: "Total país", valor: "70.8", year: 2018 },
  { agrupacion: "Total país", valor: "67.6", year: 2019 },
  { agrupacion: "Oriental", valor: "78.6", year: 2015 },
  { agrupacion: "Oriental", valor: "83.1", year: 2016 },
  { agrupacion: "Oriental", valor: "65.6", year: 2017 },
  { agrupacion: "Oriental", valor: "68.1", year: 2018 },
  { agrupacion: "Oriental", valor: "63.7", year: 2019 },
  { agrupacion: "Occidental", valor: "177.3", year: 2015 },
  { agrupacion: "Occidental", valor: "182.9", year: 2016 },
  { agrupacion: "Occidental", valor: "114.3", year: 2017 },
  { agrupacion: "Occidental", valor: "144.5", year: 2018 },
  { agrupacion: "Occidental", valor: "169.9", year: 2019 },
  { agrupacion: "Urbano", valor: "79.6", year: 2015 },
  { agrupacion: "Urbano", valor: "92.5", year: 2016 },
  { agrupacion: "Urbano", valor: "62.1", year: 2017 },
  { agrupacion: "Urbano", valor: "82.2", year: 2018 },
  { agrupacion: "Urbano", valor: "80.6", year: 2019 },
  { agrupacion: "Rural", valor: "86.5", year: 2015 },
  { agrupacion: "Rural", valor: "63.7", year: 2016 },
  { agrupacion: "Rural", valor: "87.2", year: 2017 },
  { agrupacion: "Rural", valor: "45.7", year: 2018 },
  { agrupacion: "Rural", valor: "38.9", year: 2019 },
  { agrupacion: "Total país", valor: "151", year: 2015 },
  { agrupacion: "Total país", valor: "184", year: 2016 },
  { agrupacion: "Total país", valor: "165", year: 2017 },
  { agrupacion: "Total país", valor: "147", year: 2018 },
  { agrupacion: "Total país", valor: "190", year: 2019 },
];

const result = Object.values(
  arr.reduce((r, o) => {
    if (!r[o.agrupacion]) {
      r[o.agrupacion] = [{ agrupacion: o.agrupacion }];
    }
    const item = r[o.agrupacion].find((i) => !i["col" + o.year]);
    if (item) {
      item["col" + o.year] = parseFloat(o.valor);
    } else {
      r[o.agrupacion].push({
        agrupacion: o.agrupacion,
        ["col" + o.year]: parseFloat(o.valor),
      });
    }
    return r;
  }, {})
).flat();

console.log(result);

Answer 3

您可以跟踪最后一个 yearData（您正在收集的数据组）。如果此对象中已存在给定的 col<year>，则创建一个新对象。

const result = [];
let yearData;
for (const {agrupacion, valor, year} of arr) {
  const colYear = `col${year}`;
  if (!yearData || colYear in yearData) {
    yearData = { agrupacion };
    result.push(yearData);
  }
  yearData[colYear] = +valor;
}

const arr = [
  { agrupacion: "Total país", valor: "81.8",  year: 2015 },
  { agrupacion: "Total país", valor: "86.4",  year: 2016 },
  { agrupacion: "Total país", valor: "67.3",  year: 2017 },
  { agrupacion: "Total país", valor: "70.8",  year: 2018 },
  { agrupacion: "Total país", valor: "67.6",  year: 2019 },
  { agrupacion: "Oriental",   valor: "78.6",  year: 2015 },
  { agrupacion: "Oriental",   valor: "83.1",  year: 2016 },
  { agrupacion: "Oriental",   valor: "65.6",  year: 2017 },
  { agrupacion: "Oriental",   valor: "68.1",  year: 2018 },
  { agrupacion: "Oriental",   valor: "63.7",  year: 2019 },
  { agrupacion: "Occidental", valor: "177.3", year: 2015 },
  { agrupacion: "Occidental", valor: "182.9", year: 2016 },
  { agrupacion: "Occidental", valor: "114.3", year: 2017 },
  { agrupacion: "Occidental", valor: "144.5", year: 2018 },
  { agrupacion: "Occidental", valor: "169.9", year: 2019 },
  { agrupacion: "Urbano",     valor: "79.6",  year: 2015 },
  { agrupacion: "Urbano",     valor: "92.5",  year: 2016 },
  { agrupacion: "Urbano",     valor: "62.1",  year: 2017 },
  { agrupacion: "Urbano",     valor: "82.2",  year: 2018 },
  { agrupacion: "Urbano",     valor: "80.6",  year: 2019 },
  { agrupacion: "Rural",      valor: "86.5",  year: 2015 },
  { agrupacion: "Rural",      valor: "63.7",  year: 2016 },
  { agrupacion: "Rural",      valor: "87.2",  year: 2017 },
  { agrupacion: "Rural",      valor: "45.7",  year: 2018 },
  { agrupacion: "Rural",      valor: "38.9",  year: 2019 },
  { agrupacion: "Total país", valor: "151",   year: 2015 },
  { agrupacion: "Total país", valor: "184",   year: 2016 },
  { agrupacion: "Total país", valor: "165",   year: 2017 },
  { agrupacion: "Total país", valor: "147",   year: 2018 },
  { agrupacion: "Total país", valor: "190",   year: 2019 },
];

const result = [];
let yearData;
for (const { agrupacion, valor, year } of arr) {
  const colYear = `col${year}`;
  if (!yearData || colYear in yearData) {
    yearData = { agrupacion };
    result.push(yearData);
  }
  yearData[colYear] = +valor;
}

console.log(result);

答案确实假定 arr 具有一定的一致性。也就是说，每组项目共享完全相同的年份范围（在您的数据中为 2015-2019），并且没有遗漏年份。

产生错误输出的不一致输入示例是：

const arr = [
  { agrupacion: "a", valor: "1", year: 2015 },
  { agrupacion: "a", valor: "2", year: 2016 },
  { agrupacion: "a", valor: "3", year: 2017 },
  { agrupacion: "b", valor: "4", year: 2015 },
  // 2016 missing
  { agrupacion: "b", valor: "5", year: 2017 },
  // 2015 missing
  { agrupacion: "c", valor: "6", year: 2016 },
  { agrupacion: "c", valor: "7", year: 2017 },
];

这导致：

[
  { agrupacion: "a", col2015: 1, col2016: 2, col2017: 3 },
  { agrupacion: "b", col2015: 4, col2016: 6, col2017: 5 },
  { agrupacion: "c",                         col2017: 7 },
]

如果数据中可能出现这些差距，您需要更改：

if (!yearData || colYear in yearData)

进入：

if (!yearData || agrupacion != yearData.agrupacion || colYear in yearData)

确保在 agrupacion 不同或 col<year> 已经存在时使用新的 yearData 对象。

对象数组按特定键将它们分组

array of objects group them by a specific key

javascript

arrays