获取对象数组中重复键的值答案

【问题标题】：Get values of duplicated keys in array of object获取对象数组中重复键的值
【发布时间】：2018-10-03 13:20:27
【问题描述】：

我有一个这样的对象数组。我想摆脱重复的键（名称），并且只有一个名称与数组中的所有相关值。

let array = [ 
  { name: "dimensions", value: "dimensions value 1" },
  { name: "weight",     value: "weight value 1" },
  { name: "dimensions", value: "dimensions value 2" },
  { name: "weight",     value: "weight value 3" },
  { name: "dimensions", value: "dimensions value 3" },
  { name: "weight",     value: "weight value 3" } 
]

我想把它变成这样的东西：

result = [ {
  name : "dimensions", 
  values : ["dimention value 1", "dimention value 2", "dimention value 3"] 
    }, {
  name : "weights", 
  values : ["weight value 1", "weight value 2", "weight value 3"] 
} ]

注意：数组中对象的数量是可变的。 “重量”、“尺寸”、“颜色”、“品牌”等......

到目前为止我尝试过的：

let flags = [], output = [], l = array.length;

for (let i = 0; i < l; i++) {
    if (flags[array[i].name])
      continue;

    flags[array[i].name] = array[i].name;

    output.push({
        name : array[i].name,
        values : [array[i].value]
    });
}

它会返回如下内容：

[
  { name: "dimensions", values: [ "dimensions value 1"] },
  { name: "weight",     values: [ "weight value 1"] }
]

let array = [
  { name: "dimensions", value: "dimensions value 1" },
  { name: "weight",     value: "weight value 1"},
  { name: "dimensions", value: "dimensions value 2"},
  { name: "weight",     value: "weight value 3"},
  { name: "dimensions", value: "dimensions value 3"},
  { name: "weight",     value: "weight value 3" }
]

let flags = [], output = [], l = array.length;

for (let i = 0; i < l; i++) {
  if (flags[array[i].name])
    continue;

  flags[array[i].name] = array[i].name;

  output.push({
    name: array[i].name,
    values: [array[i].value]
  });
}

console.log(output);

【问题讨论】：

标签： javascript arrays algorithm loops sorting

【解决方案1】：

虽然其他答案已经产生了您想要的输出，但您可能会发现使用键是“维度”和“权重”且它们的值是字符串数组的对象更容易。你可以用更简单的reduce：

const out = array.reduce((p, c) => {
  p[c.name] = p[c.name] || [];
  p[c.name].push(c.value);
  return p;
}, {});

输出

{
  "dimensions": [
    "dimensions value 1",
    "dimensions value 2",
    "dimensions value 3"
  ],
  "weight": [
    "weight value 1",
    "weight value 3",
    "weight value 3"
  ]
}

这只是意味着您现在可以访问属性：

out.dimensions[0]

而不是

out[0].values

这在 imo 中不太有用。

【讨论】：

【解决方案2】：

您可以使用 ES6 Map 来存储值，然后使用扩展语法 ... 来获取对象数组中的值。

let array = [ {name: "dimensions", value: "dimensions value 1"},{name: "weight", value: "weight value 1"},{name: "dimensions", value: "dimensions value 2"},{name: "weight", value: "weight value 3"},{name: "dimensions", value: "dimensions value 3"},{name: "weight", value: "weight value 3"} ]

const map = array.reduce((r, {name, value}) => {
  if(!r.has(name)) r.set(name, {name, values: [value]});
  else r.get(name).values.push(value)
  return r;
}, new Map);

const result = [...map.values()];
console.log(result)

【讨论】：

【解决方案3】：

您可以使用array#reduce 和Object.values() 根据name 对数组进行分组。

let array = [ {name: "dimensions", value: "dimensions value 1"}, {name: "weight", value: "weight value 1"}, {name: "dimensions", value: "dimensions value 2"}, {name: "weight", value: "weight value 3"}, {name: "dimensions", value: "dimensions value 3"},{name: "weight", value: "weight value 3"} ],
  result = Object.values(array.reduce((r,{name, value}) => {
    r[name] = r[name] || {name, values : []};
    r[name].values.push(value);
    return r;
  },{}));
console.log(result);

【讨论】：