具有相同鍵的物件的總和值

我有一個像這樣的資料結構。它基本上是一個物件陣列。

const dataset = [
  {
    a: { total: 2, name: "red" },
    b: { total: 3, name: "gold" },
    c: { total: 6, name: "rose" },
  },
  {
    a: { total: 10, name: "red" },
    b: { total: 7, name: "purple" },
  },
  {
    a: { total: 1, name: "pink" },
    b: { total: 14, name: "blue" },
    c: { total: 10, name: "rose" },
  },
  {
    b: { total: 2, name: "green" },
    c: { total: 18, name: "rose" },
  },
]

這是我想計算的結果：

const result = { 
  a: 13, 
  b: 26, 
  c: 34, 
}

因此，我需要total具有相同鍵的物件的值總和。我嘗試使用前面的示例來解釋自己：

const result = { 
  a: 13, // 2   10   1
  b: 26, // 3   7   14   2
  c: 34, // 6   10   18
}

請注意，鍵a, b,c可能很多（不僅是 3 個）而且我不知道它們的名稱，因為它們是動態的。

我怎樣才能做到這一點？我想{total, name}按鍵對物件進行分組，然后按總和，total但是如何？有可以幫助我的 Lodash 功能嗎？

uj5u.com熱心網友回復：

這很簡單，遍歷資料集，然后遍歷資料集行中的所有鍵：

const dataset = [
  { a: { total: 2, name: "red" }, b: { total: 3, name: "gold" }, c: { total: 6, name: "rose" } },
  { a: { total: 10, name: "red" }, b: { total: 7, name: "purple" } },
  { a: { total: 1, name: "pink" }, b: { total: 14, name: "blue" }, c: { total: 10, name: "rose" } },
  { b: { total: 2, name: "green" }, c: { total: 18, name: "rose" } },
];

const result = {};
dataset.forEach(row => {
  for (let key in row) {
    if (!result[key])
      result[key] = 0;
    result[key]  = row[key].total;
  }
});

console.log(result);

uj5u.com熱心網友回復：

您可以使用陣列 reduce ：

const dataset = [
  {
    a: { total: 2, name: "red" },
    b: { total: 3, name: "gold" },
    c: { total: 6, name: "rose" }
  },
  {
    a: { total: 10, name: "red" },
    b: { total: 7, name: "purple" }
  },
  {
    a: { total: 1, name: "pink" },
    b: { total: 14, name: "blue" },
    c: { total: 10, name: "rose" }
  },
  {
    b: { total: 2, name: "green" },
    c: { total: 18, name: "rose" }
  }
];
function getCount() {
  return dataset.reduce((countObj, nextVal) => {
    Object.keys(nextVal).forEach(key => {
      if(countObj[key]){
        countObj[key]  = nextVal[key].total;
      }else{
        countObj[key] = nextVal[key].total;
      }
    });
    return countObj;
  }, {});
}
console.log(getCount());

uj5u.com熱心網友回復：

為什么不使用reducewith for of：

const dataset = [{a: { total: 2, name: "red" }, b: { total: 3, name: "gold" }, c: { total: 6, name: "rose" }, }, {a: { total: 10, name: "red" }, b: { total: 7, name: "purple" }, }, {a: { total: 1, name: "pink" }, b: { total: 14, name: "blue" }, c: { total: 10, name: "rose" }, }, {b: { total: 2, name: "green" }, c: { total: 18, name: "rose" }, }, ];

const result = dataset.reduce((res, cur) => {
    for (const [key, value] of Object.entries(cur)) {
      res[key] = (res[key] || 0)   value.total;
    }
    return res;
}, {});

console.log(result);

uj5u.com熱心網友回復：

const map = new Map()
dataset.forEach(obj=>{
    Object.keys(obj).forEach(key=>{
        const value = obj[key]
        if(value?.total){
            if(!map.has(key)){
                map.set(key,0)
            }
            map.set(key,map.get(key) value.total)
        }
    })
})

map.forEach((v,k)=>{
    console.log(`${k}:${v}`)
})

uj5u.com熱心網友回復：

主意

構建一個總計字典，在您第一次遇到屬性時添加條目。

執行

迭代資料集中的專案，為每個專案迭代物件屬性。

假設：每個專案物件都有一個total持有數字的屬性。

function tally ( pa_dataset ) {
    let dict_totals = {}
      ;
      
    pa_dataset.forEach ( po_record => {
        Object.entries(po_record).forEach ( pa_entry => {
            let s_key   = pa_entry[0]
              , x_value = pa_entry[1]
              ;
              
            if (!dict_totals.hasOwnProperty(s_key)) { dict_totals[s_key] = 0; }
            dict_totals[s_key]  = x_value.total;
        });
    });
    
    console.log ( `Totals: ${JSON.stringify(dict_totals)}.`);
} // tally

// Test
const dataset = [
  {
    a: { total: 2, name: "red" },
    b: { total: 3, name: "gold" },
    c: { total: 6, name: "rose" },
  },
  {
    a: { total: 10, name: "red" },
    b: { total: 7, name: "purple" },
  },
  {
    a: { total: 1, name: "pink" },
    b: { total: 14, name: "blue" },
    c: { total: 10, name: "rose" },
  },
  {
    b: { total: 2, name: "green" },
    c: { total: 18, name: "rose" },
  },
];

tally(dataset);

評論

沒有專門實作所需功能的 lodash 函式。

標籤：javascript

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