如何从时间序列数据构造“嵌套”对象？

Question

我正在使用 node.js 和 sql 提取汽车的时间序列数据。

我的查询提取了 node.js 中的数据，它以 rawposdata 的形式提供：

rawposdata =
[{carID: 1234,
   contact: 'john doe',
   TimeStamp: 10:00,
   Speed = 2.3},
{carID: 1234,
   contact: 'john doe',
   TimeStamp: 11:00,
   Speed = 2.4},
{carID: 1234,
   contact: 'john doe',
   TimeStamp: 12:00,
   Speed = 2.5}
{carID: 9876,
   contact: 'bob wills',
   TimeStamp: 10:00,
   Speed = 1.1},
{carID: 9876,
   contact: 'bob wills',
   TimeStamp: 11:05,
   Speed = 1.1},
{carID: 9876,
   contact: 'bob wills',
   TimeStamp: 12:00,
   Speed = 3.2},
]

我希望它具有以下形式（数组、obj 或其他），以便我可以使用它：

mypositiondata = 
[carID: 1234,
 contact: 'john doe',
 timestamp: { ts0: 10:00,
              ts1: 11:00,
              ts2: 12:00},
 speed:     {s0: 2.3
             s1: 2.4
             s2: 2.5}],
[carID: 9876,
 contact: 'bob wills',
 timestamp: { ts0: 10:00,
              ts1: 11:05,
              ts2: 12:00},
 speed:     {s0: 1.1
             s1: 1.1
             s2: 3.2}]

我浏览了互联网上的示例，阅读下划线文档。等，但似乎我无法解决这个问题。如何构建这些数据？

我有 50 到 150 辆车要分类。 数据集中有更多静态（例如：carID）和动态（例如：速度）数据点。

Answer 1

您可以使用reduce 创建一个对象，并使用Object.values 将对象转换为数组。

let mypositiondata = Object.values(rawposdata.reduce((c, v) => {
  c[v.carID] = c[v.carID] || {carID: v.carID,contact: v.contact,timestamp: {},speed: {}}
  c[v.carID].timestamp["ts" + Object.keys(c[v.carID].timestamp).length] = v.TimeStamp;
  c[v.carID].speed["s" + Object.keys(c[v.carID].speed).length] = v.Speed;
  return c;
}, {}));

这是一个sn-p：

let rawposdata = [{carID: 1234,contact: 'john doe',TimeStamp: '10:00',Speed: 2.3},{carID: 1234,contact: 'john doe',TimeStamp: '11:00',Speed: 2.4},{carID: 1234,contact: 'john doe',TimeStamp: '12:00',Speed: 2.5},{carID: 9876,contact: 'bob wills',TimeStamp: '10:00',Speed: 1.1},{carID: 9876,contact: 'bob wills',TimeStamp: '11:05',Speed: 1.1},{carID: 9876,contact: 'bob wills',TimeStamp: '12:00',Speed: 3.2},];

let mypositiondata = Object.values(rawposdata.reduce((c, v) => {
  c[v.carID] = c[v.carID] || {carID: v.carID,contact: v.contact,timestamp: {},speed: {}}
  c[v.carID].timestamp["ts" + Object.keys(c[v.carID].timestamp).length] = v.TimeStamp;
  c[v.carID].speed["s" + Object.keys(c[v.carID].speed).length] = v.Speed;
  return c;
}, {}));

console.log(mypositiondata);

---

还有一个选择是使用 array 而不是对象来获取时间戳和速度

let rawposdata = [{carID: 1234,contact: 'john doe',TimeStamp: '10:00',Speed: 2.3},{carID: 1234,contact: 'john doe',TimeStamp: '11:00',Speed: 2.4},{carID: 1234,contact: 'john doe',TimeStamp: '12:00',Speed: 2.5},{carID: 9876,contact: 'bob wills',TimeStamp: '10:00',Speed: 1.1},{carID: 9876,contact: 'bob wills',TimeStamp: '11:05',Speed: 1.1},{carID: 9876,contact: 'bob wills',TimeStamp: '12:00',Speed: 3.2},];
let mypositiondata = Object.values(rawposdata.reduce((c,v)=>{
   c[ v.carID ] = c[ v.carID ] || {carID : v.carID, contact: v.contact, timestamp : [], speed : []}
   c[ v.carID ].timestamp.push( v.TimeStamp );
   c[ v.carID ].speed.push( v.Speed );
   return c;
},{}));
	
console.log( mypositiondata );

没有 ES6

var rawposdata = [{carID: 1234,contact: 'john doe',TimeStamp: '10:00',Speed: 2.3},{carID: 1234,contact: 'john doe',TimeStamp: '11:00',Speed: 2.4},{carID: 1234,contact: 'john doe',TimeStamp: '12:00',Speed: 2.5},{carID: 9876,contact: 'bob wills',TimeStamp: '10:00',Speed: 1.1},{carID: 9876,contact: 'bob wills',TimeStamp: '11:05',Speed: 1.1},{carID: 9876,contact: 'bob wills',TimeStamp: '12:00',Speed: 3.2},];

var temp = {};
var mypositiondata = [];

for (var k in rawposdata) {
  var v = rawposdata[k];
  if (typeof temp[v.carID] === "undefined") temp[v.carID] = {carID: v.carID, contact: v.contact, timestamp: [], speed: []};
  temp[v.carID].timestamp.push(v.TimeStamp);
  temp[v.carID].speed.push(v.Speed);
}

for (var k in temp) {
  var tSpeed = {};
  var tTStamp = {};

  for (var i in temp[k].speed) tSpeed["s" + i] = temp[k].speed[i];

  for (var i in temp[k].timestamp) tTStamp["ts" + i] = temp[k].timestamp[i];

  temp[k].speed = tSpeed;
  temp[k].timestamp = tTStamp;

  mypositiondata.push(temp[k]);
}

console.log(mypositiondata);