Angular 如何在10中获得表中多个列的平均值

我有一个函数，用于计算表中所有列中json数据的总和。我想得到每列的平均值，但最终得到的是NaN或无穷大，我做错了什么

这是我的求和实现

getSum(columnNumber) {
    let sum = 0;
    const columnNumberToPropertyMap = [
      "id",
      "teamNumber",
      "rural",
      "completed",
      "entirehouseholdabsent",
      "postponed",
      "refused",
      "vacant",
      "dwelling"     
    ];
    const property = columnNumberToPropertyMap[columnNumber];
    return this.rural.reduce((acc, curr) => {
      //const adder = Number(curr[property]) || 0;
      const adder = isNaN(Number(curr[property])) ? 0 : Number(curr[property]);
      sum = acc + adder
      return sum;
    }, 0).toFixed(2);
  }

这将给出列中所有行的总和

我怎样才能得到每列的平均值

 getSum(columnNumber) {
        let sum = 0;
        let average = 0;

        const columnNumberToPropertyMap = [
          "id",
          "teamNumber",
          "rural",
          "completed",
          "entirehouseholdabsent",
          "postponed",
          "refused",
          "vacant",
          "dwelling"     
        ];
        const property = columnNumberToPropertyMap[columnNumber];
        return this.rural.reduce((acc, curr) => {
          //const adder = Number(curr[property]) || 0;
          const adder = isNaN(Number(curr[property])) ? 0 : Number(curr[property]);
          sum = acc + adder
          average = (sum)/adder;
          return average ;
        }, 0).toFixed(2);
      }

我假设每列的下方都有NaN或无穷大

平均值=每列的总数/每列的项目数

 getSum(columnNumber) {
        let sum = 0;
        let average = 0;

        const columnNumberToPropertyMap = [
          "id",
          "teamNumber",
          "rural",
          "completed",
          "entirehouseholdabsent",
          "postponed",
          "refused",
          "vacant",
          "dwelling"     
        ];
        const property = columnNumberToPropertyMap[columnNumber];
        return this.rural.reduce((acc, curr) => {
          //const adder = Number(curr[property]) || 0;
          const adder = isNaN(Number(curr[property])) ? 0 : Number(curr[property]);
          sum = acc + adder
          average = (sum)/adder;
          return average ;
        }, 0).toFixed(2);
      }

---

要找到平均值，只需调用

getSum

，然后将其除以行数即可。因此，实施过程如下：

getAverage(columnNumber) {
    let sum = getSum(columnNumber);
    let count = this.rural.length;
    return sum / count;
}

---

或者，在一行中，

返回getSum（columnNumber）/this.rural.length
您是否尝试在代码中记录
sum
、
adder
和
average
的值？这可以帮助您跟踪计算Hi@PMO1948看到我的问题了，加法器有行数，但是我如何获得行数的计数并使用它呢？获取您的行数组并调用
.length
以获得总计数。如果
rural
是你的数组，那么调用
this.rural.length
Hi@PMO1948这是一个示例代码，你能帮助我，记录
adder
？
console.log（'agemen.length:'，agemen.length'）中的行数吗
在打印getSum后添加此项，您可以看到总长度return sum/count抛出错误
算术运算的左侧必须是'any'、'number'、'bigint'类型或枚举类型。
try
让sum=+getSum（columnNumber）
将结果转换为数字记录结果时，它会显示什么？或者，尝试
让sum:number=getSum（columnNumber）
或将
getSum
的返回类型设置为
number