将对象数组转换为特定格式？

Question

我有以下一组数据，它们采用数组中对象的格式。


  const columns = [
    {
      "usage": 395226,
      "population": 1925117,
      "value": 21,
      "abv": "MN"
    },
    {
      "usage": 893129,
      "population": 4327541,
      "value": 21,
      "abv": "IL"
    }
  ]

我需要将上面的一组数据转换成下面显示的格式。我被困在这里有一段时间了。我尝试编写一个函数将其转换为所需的数据格式，但没有成功。


let columns = [ 
                 ["abv", "population"], 
                 ["MN", 1925117], 
                 ["IL", 4327541] 
              ]

如果有人能帮我解决这个问题，那将是一个很大的帮助。提前致谢:)

Answer 1

这能解决您的问题吗？

const columns = [
    {
      "usage": 395226,
      "population": 1925117,
      "value": 21,
      "abv": "MN"
    },
    {
      "usage": 893129,
      "population": 4327541,
      "value": 21,
      "abv": "IL"
    }
  ]
var k = [["abv", "population"]];
for(var i = 0; i < columns.length; i++){
    k.push([columns[i].abv, columns[i].population]);
}
console.log(k) // Expected expected output

如果您需要，这里有一个通用的实现。

var names = ["abv", "population"];
var k = GetPropertiesInArray(columns, names); //[["abv", "population"]];

function GetPropertiesInArray(columns, names){
    var m = [];
    m.push(names);
    for(var i = 0; i < columns.length; i++){
        var item = [];
        for(var j in names){
            item.push(columns[i][names[j]]);
        }
        m.push(item);
    }

    return m;
}

console.log(k);//Expected output

Answer 2

我会用减速器来做：

 const cols = [
    {
      "usage": 395226,
      "population": 1925117,
      "value": 21,
      "abv": "MN"
    },
    {
      "usage": 893129,
      "population": 4327541,
      "value": 21,
      "abv": "IL"
    }
  ]

cols.reduce(function(acc, current) {
  acc.push([current.abv, current.population])
  return acc;
}, ["abv", "population"]);

或者如果您不喜欢使用 push：

cols.reduce(function(acc, current) {

 acc = [
  ...acc,
  [current.abv, current.population]
 ]

 return acc;
}, ["abv", "population"]);

示例：https://jsbin.com/gudivuhuro/edit?html,js,console

Answer 3

您的第一个数据在所需输出中似乎是静态的：

const columns = [
    {
      "usage": 395226,
      "population": 1925117,
      "value": 21,
      "abv": "MN"
    },
    {
      "usage": 893129,
      "population": 4327541,
      "value": 21,
      "abv": "IL"
    }
  ];
  
  let cols = [];
  if (columns.length) {
      cols.push(["abv", "population"]);
      columns.forEach(item => {
          cols.push([item.abv, item.population])
      });
  }
  console.log(cols);

Answer 4

我最终会使用这样的东西：

const columns = [
    {
      "usage": 395226,
      "population": 1925117,
      "value": 21,
      "abv": "MN"
    },
    {
      "usage": 893129,
      "population": 4327541,
      "value": 21,
      "abv": "IL"
    }
];

let converted = columns.map((c) => [c.abv, c.population]);
converted.unshift(["abv", "population"]);

将对象数组转换为特定格式？

convert an array of objects into a specific format?

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