将对象数组转换为对象的最佳方法

Best way to convert array of objects into Object?

本文关键字：对象 最佳 方法 转换 数组      更新时间：2023-09-26

我需要将对象数组转换为object。我已经完成了下面的逻辑。有没有最好的办法来处理这件事?

拉提琴的版本

var before = [{
  "x": ["2015-10-14T01:59:59.999+05:30", "2015-10-14T03:59:59.998+05:30", "2015-10-14T05:59:59.997+05:30", "2015-10-14T07:59:59.996+05:30", "2015-10-14T09:59:59.995+05:30", "2015-10-14T11:59:59.994+05:30", "2015-10-14T13:59:59.993+05:30", "2015-10-14T15:59:59.992+05:30", "2015-10-14T17:59:59.991+05:30", "2015-10-14T19:59:59.990+05:30", "2015-10-14T21:59:59.989+05:30", "2015-10-14T23:59:59.988+05:30"]
}, {
  "CleanCoal": ["0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00"]
}, {
  "Middelings": ["0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00"]
}, {
  "Prime": ["0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00"]
}, {
  "SpiralProd": ["0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00"]
}];
var after = {};
for (var i = 0; i < before.length; i++) {
  var keys = Object.keys(before[i]);
  after[keys] = before[i][keys];
}
console.log(after)
document.writeln(JSON.stringify(after))

可以使用forEach来遍历数组，如果对象中有多个元素，则忘记遍历嵌套数组。

因此，所讨论的代码不适用于

var arr = [{'a': 'b', 'c': 'd'}];


var before = [{
  "x": ["2015-10-14T01:59:59.999+05:30", "2015-10-14T03:59:59.998+05:30", "2015-10-14T05:59:59.997+05:30", "2015-10-14T07:59:59.996+05:30", "2015-10-14T09:59:59.995+05:30", "2015-10-14T11:59:59.994+05:30", "2015-10-14T13:59:59.993+05:30", "2015-10-14T15:59:59.992+05:30", "2015-10-14T17:59:59.991+05:30", "2015-10-14T19:59:59.990+05:30", "2015-10-14T21:59:59.989+05:30", "2015-10-14T23:59:59.988+05:30"]
}, {
  "CleanCoal": ["0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00"]
}, {
  "Middelings": ["0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00"]
}, {
  "Prime": ["0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00"]
}, {
  "SpiralProd": ["0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00"]
}];
var after = {};
before.forEach(function(obj) {
  // obj here is the element of the array, i.e. object
  // Looping over all the keys of the object
  Object.keys(obj).forEach(function(key) {
    // key here is the key of the object
    after[key] = obj[key];
  });
});
console.log(after);
document.writeln('<pre>' + JSON.stringify(after, 0, 2) + '</pre>');

在最新的浏览器[ecmascript 5]中，我们有reduce返回一个对象

尝试下面

var before = [{"x":["2015-10-14T01:59:59.999+05:30","2015-10-14T03:59:59.998+05:30","2015-10-14T05:59:59.997+05:30","2015-10-14T07:59:59.996+05:30","2015-10-14T09:59:59.995+05:30","2015-10-14T11:59:59.994+05:30","2015-10-14T13:59:59.993+05:30","2015-10-14T15:59:59.992+05:30","2015-10-14T17:59:59.991+05:30","2015-10-14T19:59:59.990+05:30","2015-10-14T21:59:59.989+05:30","2015-10-14T23:59:59.988+05:30"]},{"CleanCoal":["0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00"]},{"Middelings":["0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00"]},{"Prime":["0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00"]},{"SpiralProd":["0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00","0.00"]}];
var object = before.reduce(function(o, v, i) {
  o[i] = v;
  return o;
}, {});
console.log(object);

点击这里http://jsfiddle.net/pscytrgj/

我们在JavaScript中使用了最好的函数式编程:

使用reduce，我们不需要在外部作用域中添加临时变量。

for (var i in obj)一般比Obj.keys(obj).forEach快:https://jsperf.com/for-in-versus-object-keys-foreach

var before = [{
  "x": ["2015-10-14T01:59:59.999+05:30", "2015-10-14T03:59:59.998+05:30", "2015-10-14T05:59:59.997+05:30", "2015-10-14T07:59:59.996+05:30", "2015-10-14T09:59:59.995+05:30", "2015-10-14T11:59:59.994+05:30", "2015-10-14T13:59:59.993+05:30", "2015-10-14T15:59:59.992+05:30", "2015-10-14T17:59:59.991+05:30", "2015-10-14T19:59:59.990+05:30", "2015-10-14T21:59:59.989+05:30", "2015-10-14T23:59:59.988+05:30"]
}, {
  "CleanCoal": ["0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00"]
}, {
  "Middelings": ["0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00"]
}, {
  "Prime": ["0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00"]
}, {
  "SpiralProd": ["0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00"]
}];
var after = before.reduce(function(dst, src){
  // import every key: val in src into dst
  // and keep doing it for every element in the array.
  for (var key in src) 
    if ({}.hasOwnProperty.call(src, key)) 
      dst[key] = src[key];
  return dst;
}, {}); // start with an empty object to avoid modifying items in before array.
document.writeln("<pre>" + JSON.stringify(after, null, 4) + "</pre>")

您可以通过JSON.stringify() 

var before = [{
  "x": ["1", "2"],
  y: {
    a: 3
  }
}, {
  "CleanCoal": ["0.00", "0.00"],
  b: 4
}, {
  "Middelings": ["0.00", "0.00"]
}, {
  "Prime": ["0.00", "0.00", "0.00"]
}, {
  "SpiralProd": ["0.00", "0.00", "0.00"]
}];
var after = {};
var b = "",
  i = -1;
while (before[++i]) {
  var str = JSON.stringify(before[i]);
  b += str.slice(1, str.length - 1);
  if (before[i + 1]) b += ",";
}
after = JSON.parse("{" + b + "}");
console.log(after);
document.write("<pre>" + JSON.stringify(after, 0, 3) + "</pre>")

Object.assign呢?

var before = [{
  "x": ["2015-10-14T01:59:59.999+05:30", "2015-10-14T03:59:59.998+05:30", "2015-10-14T05:59:59.997+05:30", "2015-10-14T07:59:59.996+05:30", "2015-10-14T09:59:59.995+05:30", "2015-10-14T11:59:59.994+05:30", "2015-10-14T13:59:59.993+05:30", "2015-10-14T15:59:59.992+05:30", "2015-10-14T17:59:59.991+05:30", "2015-10-14T19:59:59.990+05:30", "2015-10-14T21:59:59.989+05:30", "2015-10-14T23:59:59.988+05:30"]
}, {
  "CleanCoal": ["0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00"]
}, {
  "Middelings": ["0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00"]
}, {
  "Prime": ["0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00"]
}, {
  "SpiralProd": ["0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00", "0.00"]
}];
var after = {};
before.map(function(i){
  return  Object.assign(after,i);
})
console.log(after)
document.writeln(JSON.stringify(after))

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