如何映射陣列未命名的物件陣列

我有一個物件陣列，我需要在其中找到每個值陣列的總和。看起來像這樣

 '1664625533491050': [
    380.942, 394.71, 387.936, 273.902,
     137.58, 133.82,  66.471,  58.616,
     45.966, 36.849,  49.002,  32.275,
     65.209, 34.679,  60.806,  46.576,
     132.89, 62.005,   0.386,    0.09,
      0.005,  0.601,   0.004,   0.316,
      0.227,  0.185,   0.206,   0.142,
        0.1,  0.121,   0.089,   0.016,
      0.033,  0.008,       0,   0.002,
      0.001
  ],
  '1664625594588444': [
    381.931, 394.71, 387.936, 283.902,
    146.365, 133.82,  66.471,  58.616,
     45.966, 36.849,  49.002,  32.275,
     64.953, 34.679,  60.806,  46.576,
    132.889, 68.005,   0.386,    0.09,
      0.005,  0.601,   0.004,   0.316,
      0.227,  0.185,   0.206,   0.142,
        0.1,  0.121,   0.089,   0.016,
      0.033,  0.008,       0,   0.002,
      0.001
  ]
}

對于每個物件，我需要找到每個陣列的總和。我相信我需要映射和減少每一個，但我不確定如何參考每個陣列

function getSum(obj) {
      for (const key in obj) {
        const firstStep = obj[key];
        const secondStep = firstStep.map(x => x/*not sure how to reference*/);
        const thirdStep = secondStep.reduce((a, b) => a   b);
        obj[key] = thirdStep
  
        return obj
      }

如何參考陣列以便獲得每個物件陣列的總和？

例子

'1664625533491050': 2345.789,
'1664625594588444': 1789.587
// those aren't the actual totals just example of what Im looking to get

uj5u.com熱心網友回復：

不確定您在嘗試什么.map-根本不需要

看這段代碼沒有那一步

注意：您的代碼return在 for 回圈中執行了一次操作，因此只處理了物件的一個??元素；

注意 2：這會改變傳入的物件 - 正如您從console.log(input)

const input = {
    '1664625533491050': [
        380.942, 394.71, 387.936, 273.902,
        137.58, 133.82,  66.471,  58.616,
        45.966, 36.849,  49.002,  32.275,
        65.209, 34.679,  60.806,  46.576,
        132.89, 62.005,   0.386,    0.09,
        0.005,  0.601,   0.004,   0.316,
        0.227,  0.185,   0.206,   0.142,
        0.1,  0.121,   0.089,   0.016,
        0.033,  0.008,       0,   0.002,
        0.001
    ],
    '1664625594588444': [
        381.931, 394.71, 387.936, 283.902,
        146.365, 133.82,  66.471,  58.616,
        45.966, 36.849,  49.002,  32.275,
        64.953, 34.679,  60.806,  46.576,
        132.889, 68.005,   0.386,    0.09,
        0.005,  0.601,   0.004,   0.316,
        0.227,  0.185,   0.206,   0.142,
        0.1,  0.121,   0.089,   0.016,
        0.033,  0.008,       0,   0.002,
        0.001
    ]
};
function getSum(obj) {
    for (const key in obj) {
        const array = obj[key];
        const sum = array.reduce((a, b) => a   b);
        obj[key] = sum;
    }
    return obj;
}
getSum(input);
console.log(input);

如果您不想改變傳入的物件，那么代碼很簡單

const input = {
    '1664625533491050': [
        380.942, 394.71, 387.936, 273.902,
        137.58, 133.82,  66.471,  58.616,
        45.966, 36.849,  49.002,  32.275,
        65.209, 34.679,  60.806,  46.576,
        132.89, 62.005,   0.386,    0.09,
        0.005,  0.601,   0.004,   0.316,
        0.227,  0.185,   0.206,   0.142,
        0.1,  0.121,   0.089,   0.016,
        0.033,  0.008,       0,   0.002,
        0.001
    ],
    '1664625594588444': [
        381.931, 394.71, 387.936, 283.902,
        146.365, 133.82,  66.471,  58.616,
        45.966, 36.849,  49.002,  32.275,
        64.953, 34.679,  60.806,  46.576,
        132.889, 68.005,   0.386,    0.09,
        0.005,  0.601,   0.004,   0.316,
        0.227,  0.185,   0.206,   0.142,
        0.1,  0.121,   0.089,   0.016,
        0.033,  0.008,       0,   0.002,
        0.001
    ]
};

function betterGetSum(obj) {
    return Object.fromEntries(Object.entries(obj).map(([key, array]) => [key, array.reduce((a, b) => a   b)]));
}
console.log(betterGetSum(input));

uj5u.com熱心網友回復：

你可以用reduce它來做

let data={
'1664625533491050': [
    380.942, 394.71, 387.936, 273.902,
     137.58, 133.82,  66.471,  58.616,
     45.966, 36.849,  49.002,  32.275,
     65.209, 34.679,  60.806,  46.576,
     132.89, 62.005,   0.386,    0.09,
      0.005,  0.601,   0.004,   0.316,
      0.227,  0.185,   0.206,   0.142,
        0.1,  0.121,   0.089,   0.016,
      0.033,  0.008,       0,   0.002,
      0.001
  ],
  '1664625594588444': [
    381.931, 394.71, 387.936, 283.902,
    146.365, 133.82,  66.471,  58.616,
     45.966, 36.849,  49.002,  32.275,
     64.953, 34.679,  60.806,  46.576,
    132.889, 68.005,   0.386,    0.09,
      0.005,  0.601,   0.004,   0.316,
      0.227,  0.185,   0.206,   0.142,
        0.1,  0.121,   0.089,   0.016,
      0.033,  0.008,       0,   0.002,
      0.001
  ]
}

let keys = Object.keys(data)
let result = {}
keys.forEach(k => {
  let value = data[k].reduce((a,v) => a  v,0)
  result[k]=value
})

console.log(result)

uj5u.com熱心網友回復：

Array.reduce()您可以通過使用方法簡單地實作這一點。

現場演示：

const obj = {
  '1664625533491050': [
    380.942, 394.71, 387.936, 273.902,
    137.58, 133.82,  66.471,  58.616,
    45.966, 36.849,  49.002,  32.275,
    65.209, 34.679,  60.806,  46.576,
    132.89, 62.005,   0.386,    0.09,
    0.005,  0.601,   0.004,   0.316,
    0.227,  0.185,   0.206,   0.142,
    0.1,  0.121,   0.089,   0.016,
    0.033,  0.008,       0,   0.002,
    0.001
  ],
  '1664625594588444': [
    381.931, 394.71, 387.936, 283.902,
    146.365, 133.82,  66.471,  58.616,
    45.966, 36.849,  49.002,  32.275,
    64.953, 34.679,  60.806,  46.576,
    132.889, 68.005,   0.386,    0.09,
    0.005,  0.601,   0.004,   0.316,
    0.227,  0.185,   0.206,   0.142,
    0.1,  0.121,   0.089,   0.016,
    0.033,  0.008,       0,   0.002,
    0.001
  ]
};

Object.keys(obj).forEach(key => {
  obj[key] = obj[key].reduce((sum, elem) => sum   elem);
})

console.log(obj);

uj5u.com熱心網友回復：

你可以用，for in。看

const object = { a: 1, b: 2, c: 3 };

for (const property in object) {
  console.log(`${property}: ${object[property]}`);
}

標籤：javascript数组映射减少

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