具有相同鍵的對象的總和值

Question

我有一個像這樣的數據結構。 它基本上是一個對象數組。

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，我需要具有相同鍵的對象的total 。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？ 我想按鍵對對象{total, name}進行分組，然后按total求和，但如何？ 有可以幫助我的 Lodash 功能嗎？

Answer 1

這很簡單，遍歷數據集，然后遍歷數據集行中的所有鍵：

 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);

Answer 2

為什么不使用reduce和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);

Answer 3

您可以使用數組 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());

Answer 4

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

迭代數據集中的項目，為每個項目迭代對象屬性。

假設：每個 item 對象都有一個屬性total持有一個數字。

 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; }); }); return 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" }, }, ]; console.log ( 'Totals:' ); console.log ( tally(dataset));

評論

沒有專門實現所需功能的 lodash 函數。

Answer 5

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}`)
})