如何对对象的值求和并将其推送到数组中

Question

我有一个动态的对象数组，取决于表中行的选择。一个例子：

var obj = [
            { name: "test1",  totalCosts: 45560, actualTotalCosts: 652112, riskCosts: 65442 },
            { name: "test2",  totalCosts: 3434,  actualTotalCosts: 25252,   riskCosts: 34234 },
            { name: "test3",  totalCosts: 23123, actualTotalCosts: 23242,  riskCosts: 0 },
        ];

生成此数组后，我想调用一个函数，该函数在此数组中再推一行并将其命名为“总计”并将所有受尊重的值相加，如下所示：

{name: "total", totalCosts:72117, actualTotalCosts:700606, riskCosts: 99676 }

obj[0].totalCosts + obj[1].totalCosts + obj[2].totalCosts = obj[3].totalCosts

我尝试用我有限的知识编写一个，但该函数不是总结所有三个对象的值，而是将整个对象总结为一个。

            function sum1( obj ) {
            var result1 = [];
            for (var i = 0; i < obj.length; i++) {
                var sum = 0, arr = [];
                for (var key in obj[i]) {
                    if (key != 'name') {
                        sum += obj[i][key];
                        arr.push(sum[key]);
                    }

                }
                result1.push(arr);
                return result1;
            }
        }

请提供一个函数，可以对所有对象求和并返回包含总数的数组。我也尝试使用 d3.sum 但没有成功。

Answer 1

您可以借助 d3.sum 采用函数式方法...

  obj.push(d3.keys(obj[0])                //get the keys from obj[0]
    .reduce(function(sumRow, sumCol) {    //construct a summary row
      var isNum = !isNaN(obj[0][sumCol])  //only sum numeric fields
      return (sumRow[sumCol] = (isNum ? d3.sum(obj, function(row) {
        return row[sumCol]                //accessor for the column for  d3.sum
      }) : "All"), sumRow)                //append the sum col to the sum row object
    },{}));                               //initial value for reduce is {}

---

工作示例

  (function() {
    var obj = [{
      name: "test1",
      name2: "type1",
      totalCosts: 45560,
      actualTotalCosts: 652112,
      riskCosts: 65442
    }, {
      name: "test2",
      name2: "type2",
      totalCosts: 3434,
      actualTotalCosts: 25252,
      riskCosts: 34234
    }, {
      name: "test3",
      name2: "type3",
      totalCosts: 23123,
      actualTotalCosts: 23242,
      riskCosts: 0
    }];

    obj.push(d3.keys(obj[0])
      .reduce(function(sumRow, sumCol) {
        var isNum = !isNaN(obj[0][sumCol])
        return (sumRow[sumCol] = (isNum ? d3.sum(obj, function(row) {
          return row[sumCol]
        }) : "All"), sumRow)
      }, {}));

    d3.select("#result").text(JSON.stringify(obj))
  })()

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>
<div id="result"></div>

Answer 2

注意：重要的是要意识到您所调用的 var obj 实际上是一个数组。

话虽如此，您可以遍历数组并执行以下操作：

function sumAll(arr) {

  // Create variables for the costs we're tracking
  var totalCosts = 0;
  var actualTotalCosts = 0;
  var riskCosts = 0;

  arr.forEach(function(elem) {
    // At each iteration of our loop, increase the appropriate variables by their appropriate values
    if (elem.hasOwnProperty('totalCosts')) {
      totalCosts += elem.totalCosts;
    }
    if (elem.hasOwnProperty('actualTotalCosts')) {
    actualTotalCosts += elem.actualTotalCosts;
    }
    if (elem.hasOwnProperty('riskCosts')) {
      riskCosts += elem.riskCosts
    }
  });

  // Return an object with the information we'd like to have
  return {
    name: 'total',
    totalCosts: totalCosts,
    actualTotalCosts: actualTotalCosts,
    riskCosts: riskCosts
  }
}

来自您的代码：

var obj = [
            { name: "test1",  totalCosts: 45560, actualTotalCosts: 652112, riskCosts: 65442 },
            { name: "test2",  totalCosts: 3434,  actualTotalCosts: 25252,   riskCosts: 34234 },
            { name: "test3",  totalCosts: 23123, actualTotalCosts: 23242,  riskCosts: 0 },
        ];

调用我的函数：

sumAll(obj) // {name: "total", totalCosts: 72117, actualTotalCosts: 700606, riskCosts: 99676}