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在JavaScript中,合并日期-时间序列的有效算法是什么?

anychart algorithm javascript

-1

SkyWalker · 技术社区 · 1 年前

我有以下时间序列列表作为输入:

const ts1 = [
  ['2023-01-20', 1],
  ['2023-01-21', 2],
  ['2023-01-22', 3],
  ['2023-01-23', 4],
];

const ts2 = [
  ['2023-01-18', 5],
  ['2023-01-19', 6],
  ['2023-01-20', 7],
  ['2023-01-21', 8]
];

const ts3 = [
  ['2023-01-21', 9],
  ['2023-01-22', 10],
  ['2023-01-23', 11],
  ['2023-01-24', 12]
];

我希望输出是合并的(列堆叠的)版本,如下所示:

const output = [
  ['2023-01-18', null,    5, null],
  ['2023-01-19', null,    6, null],
  ['2023-01-20',    1,    7, null],
  ['2023-01-21',    2,    8,    9],
  ['2023-01-22',    3, null,   10],
  ['2023-01-23',    4, null,   11],
  ['2023-01-24', null, null,   12]
];

为了提供更多的上下文,我重用了一个REST API,它提供了单独的时间序列,我需要编译AnyChart所需的tableData格式。

1 回复 | 直到 1 年前

AKX Bryan Oakley 1 年前

我会选择这样的东西

const merged = {};

let tses = [ts1, ts2, ts3];
for (let i = 0; i < tses.length; i++) {
  for (const [t, v] of tses[i]) {
    if (!merged[t]) merged[t] = new Array(tses.length).fill(null);
    merged[t][i] = v;
  }
}

console.log(Object.entries(merged).map(([t, vs]) => [t, ...vs]));

此输出

[
  [ '2023-01-20', 1, 7, null ],
  [ '2023-01-21', 2, 8, 9 ],
  [ '2023-01-22', 3, null, 10 ],
  [ '2023-01-23', 4, null, 11 ],
  [ '2023-01-18', null, 5, null ],
  [ '2023-01-19', null, 6, null ],
  [ '2023-01-24', null, null, 12 ]
]

正如预期的那样。

对于排序顺序(因为键是按字典排序的),请执行

console.log(Object.keys(merged).sort().map(key => [key, ...merged[key]]));

相反:

[
  [ '2023-01-18', null, 5, null ],
  [ '2023-01-19', null, 6, null ],
  [ '2023-01-20', 1, 7, null ],   
  [ '2023-01-21', 2, 8, 9 ],      
  [ '2023-01-22', 3, null, 10 ],  
  [ '2023-01-23', 4, null, 11 ],
  [ '2023-01-24', null, null, 12 ]
]

Unmitigated 1 年前

一种替代方法 Array#reduce 和 nullish coalescing assignment 以下为:

const ts1=[["2023-01-20",1],["2023-01-21",2],["2023-01-22",3],["2023-01-23",4],],ts2=[["2023-01-18",5],["2023-01-19",6],["2023-01-20",7],["2023-01-21",8]],ts3=[["2023-01-21",9],["2023-01-22",10],["2023-01-23",11],["2023-01-24",12]];
const res = Object.entries([ts1, ts2, ts3].reduce((acc, curr, i, t) => {
  curr.forEach(([k, v]) => (acc[k] ??= Array(t.length).fill(null))[i] = v);
  return acc;
}, {})).sort().map(([k, v]) => [k, ...v]);
console.log(res);

suchislife 1 年前

您可以创建一种高效的算法来合并时间序列,方法是首先将所有日期和值放在哈希图中,然后将其转换为数组。

这是一种有效的方法,因为哈希映射操作(插入和查找)通常为O(1),这使得算法比直接比较和插入数组更快。

以下是一个示例:

const ts1 = [
  ['2023-01-20', 1],
  ['2023-01-21', 2],
  ['2023-01-22', 3],
  ['2023-01-23', 4],
];

const ts2 = [
  ['2023-01-18', 5],
  ['2023-01-19', 6],
  ['2023-01-20', 7],
  ['2023-01-21', 8]
];

const ts3 = [
  ['2023-01-21', 9],
  ['2023-01-22', 10],
  ['2023-01-23', 11],
  ['2023-01-24', 12]
];

function mergeTimeSeries(...timeSeries) {
  const hashMap = {};
  let seriesIndex = 1;
  
  for (const ts of timeSeries) {
    for (const [date, value] of ts) {
      if (!hashMap[date]) {
        hashMap[date] = Array(timeSeries.length + 1).fill(null);
        hashMap[date][0] = date;
      }
      hashMap[date][seriesIndex] = value;
    }
    seriesIndex++;
  }

  // Convert hashMap into array and sort by date
  const result = Object.values(hashMap).sort((a, b) => new Date(a[0]) - new Date(b[0]));

  return result;
}

const output = mergeTimeSeries(ts1, ts2, ts3);

console.log(output);