[英]how to get a cumulative total array from 3 two dimensional arrays
我有 3 個二維數組,如下所示,它們是用於在圖形上繪制線條的系列數據,鍵是時間戳。
const arr1 = [[1641013200000,1881],[1643691600000,38993],[1646110800000,41337],[1648785600000,78856],[1651377600000,117738],[1654056000000,119869],[1656648000000,157799],[1659326400000,196752],[1662004800000,199061],[1664596800000,237034],[1667275200000,239153],[1669870800000,269967]]
const arr2 = [[1641013200000,1302],[1643691600000,3347],[1646110800000,4754],[1648785600000,6948],[1651377600000,9725],[1654056000000,11314],[1656648000000,13787],[1659326400000,16666],[1662004800000,18370],[1664596800000,20876],[1667275200000,22384],[1669870800000,23560]]
const arr3 = [[1643691600000,67350],[1648785600000,134700],[1651377600000,202148],[1654056000000,202270],[1656648000000,269843],[1659326400000,337346],[1662004800000,337470],[1664596800000,404861],[1667275200000,404889],[1669870800000,472239]]
我想繪制另一條系列線,給出所有三個數組值的累計總和(注意:如果兩個數組中都不存在時間戳,請添加先前的索引值)
const totalArray = [
[1641013200000,3183],[1643691600000, 109690],[1646110800000, 113441],[1648785600000, 220504],
[1651377600000, 329611],[1654056000000, 333453],[1656648000000, 441429],[1659326400000, 550764],
[1662004800000, 554901],[1664596800000, 662771],[1667275200000, 666426],[1669870800000, 765766]
]
我試過這個,但是由於時間戳不存在於任何一個中,所以有些值不正確
方法:
const arr1 = [[1641013200000,1881],[1643691600000,38993],[1646110800000,41337],[1648785600000,78856],[1651377600000,117738],[1654056000000,119869],[1656648000000,157799],[1659326400000,196752],[1662004800000,199061],[1664596800000,237034],[1667275200000,239153],[1669870800000,269967]];
const arr2 = [[1641013200000,1302],[1643691600000,3347],[1646110800000,4754],[1648785600000,6948],[1651377600000,9725],[1654056000000,11314],[1656648000000,13787],[1659326400000,16666],[1662004800000,18370],[1664596800000,20876],[1667275200000,22384],[1669870800000,23560]];
const arr3 = [[1643691600000,67350],[1648785600000,134700],[1651377600000,202148],[1654056000000,202270],[1656648000000,269843],[1659326400000,337346],[1662004800000,337470],[1664596800000,404861],[1667275200000,404889],[1669870800000,472239]];
const calculateTotal = () => {
var ret;
for(let a3 of arr3) {
var index = arr1.map(function(el){return el[0];}).indexOf(a3[0]);
console.log(index);
if (index === -1) {
ret = arr1[index][0];
console.log(ret);
}
}
let unsortedArr = arr1.concat(arr2, arr3);
var sortedArray = unsortedArr.sort((a, b) => a[0] - b[0]);
var added = addArray(sortedArray);
console.log("Curent Output: " + JSON.stringify(added));
}
const addArray = (tuples) => {
var hash = {},
keys = [];
tuples.forEach(function (tuple) {
var key = tuple[0],
value = tuple[1];
if (hash[key] === undefined) {
keys.push(key);
hash[key] = value;
} else {
hash[key] += value;
}
});
return keys.map(function (key) {
return([key, hash[key]]);
});
}
calculateTotal();
[代碼沙盒鏈接][1] [1]:https://codesandbox.io/s/tender-blackburn-rgwns3?file=/src/App.js:1349-1761
有可能實現這一目標嗎?
在你的代碼中有這樣的:
if (index === -1) {
ret = arr1[index][0];
但由於arr1[-1]
未定義,該分配將失敗。
然后當你這樣做時:
let unsortedArr = arr1.concat(arr2, arr3);
...當三個數組中的任何一個具有“缺失”時間戳時,您最終得到一個不知道使用默認值(來自先前索引)的數組。
我會建議這種方法:
這是一個實現:
function mergeArrays(...arrays) { const map = new Map(arrays.flatMap(arr => arr.map(([stamp]) => [stamp, []]))); arrays.forEach((arr, i) => { for (const [timeStamp, value] of arr) { map.get(timeStamp)[i] = value; } }); const state = Array(arrays.length).fill(0); return Array.from(map).sort(([a], [b]) => a - b).map(([timeStamp, arr], i) => [timeStamp, state.reduce((sum, prev, j) => sum + (state[j] = arr[j]?? prev), 0)] ); } // Example run const arr1 = [[1641013200000,1881],[1643691600000,38993],[1646110800000,41337],[1648785600000,78856],[1651377600000,117738],[1654056000000,119869],[1656648000000,157799],[1659326400000,196752],[1662004800000,199061],[1664596800000,237034],[1667275200000,239153],[1669870800000,269967]]; const arr2 = [[1641013200000,1302],[1643691600000,3347],[1646110800000,4754],[1648785600000,6948],[1651377600000,9725],[1654056000000,11314],[1656648000000,13787],[1659326400000,16666],[1662004800000,18370],[1664596800000,20876],[1667275200000,22384],[1669870800000,23560]]; const arr3 = [[1643691600000,67350],[1648785600000,134700],[1651377600000,202148],[1654056000000,202270],[1656648000000,269843],[1659326400000,337346],[1662004800000,337470],[1664596800000,404861],[1667275200000,404889],[1669870800000,472239]]; const result = mergeArrays(arr1, arr2, arr3); console.log(result);
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