求和嵌套数组

Question

我在对象数组中有一个数组，我想对嵌套数组中的值求和。

[{BenefitType:'401k',
   Beneficiaries: [{Name: 'PersonA', Percentage: 20},
                   {Name: 'PersonB', Percentage: 30},
                   {Name: 'PersonC', Percentage: 50}]
},
 {BenefitType:'IRA',
   Beneficiaries: [{Name: 'PersonA', Percentage: 15},
                   {Name: 'PersonB', Percentage: 45},
                   {Name: 'PersonC', Percentage: 40}]
}];

我想按福利类型汇总所有百分比，以便401k = 100和IRA = 100。

我有以下代码，但它为我提供了百分比的总计，而不是每种福利类型的总计：

var myTotal = 0;

for(var i = 0; i < data.benefit_type.length; i++) {
    for(var j=0; j < data.benefit_type[i].beneficiaries.length; j++) {
        myTotal += parseInt(data.benefit_type[i].beneficiaries[j].percentage); 
        data.benefit_type[i].percent_total = myTotal;

    } 
}

我缺少什么来解决这个问题？

Answer 1

您可以使用.forEach() 遍历所有对象并使用.reduce() 对内部数组求和：

let array = [{BenefitType:'401k',
   Beneficiaries: [{Name: 'PersonA', Percentage: 20},
                   {Name: 'PersonB', Percentage: 30},
                   {Name: 'PersonC', Percentage: 50}]
},
 {BenefitType:'IRA',
   Beneficiaries: [{Name: 'PersonA', Percentage: 15},
                   {Name: 'PersonB', Percentage: 45},
                   {Name: 'PersonC', Percentage: 40}]
}];


array.forEach(x => x.TotalPercentage = x.Beneficiaries.reduce((val, cur) => val + cur.Percentage, 0));

console.log(array);

编辑：

要使用双 for 循环修复代码，您应该在离开内部循环时将 myTotal 变量设置为零：

for(var i = 0; i < data.benefit_type.length; i++) {
    for(var j=0; j < data.benefit_type[i].Beneficiaries.length; j++) {
        myTotal += data.benefit_type[i].Beneficiaries[j].Percentage; 
        data.benefit_type[i].percent_total = myTotal;
    }
    myTotal = 0;
}