如何按idInteraction属性值汇总qualification？代码问题求修正

问题描述 #

我想要根据数组中对象的idInteraction属性值，汇总对应qualification字段的总和。尝试通过abilityOrder迭代，但没法正确匹配idInteraction，当前代码如下：

var arrayQ = [ '{"idInteraction":"{9ae8653e-99ef-11e9-9e08-90c283d38b9a}","abilityOrder":1, "qualification":40}', '{"idInteraction":"{9ae8653e-99ef-11e9-9e08-90c283d38b9a}","abilityOrder":2, "qualification":60}', '{"idInteraction":"{8ae8653e-99ef-11e9-9e08-90c283d38b9a}","abilityOrder":1, "qualification":20}', '{"idInteraction":"{8ae8653e-99ef-11e9-9e08-90c283d38b9a}","abilityOrder":2, "qualification":30}' ];
var q = 0;
function findMinMax(arr) {
 let min = JSON.parse(arr[0]).abilityOrder, max = JSON.parse(arr[0]).abilityOrder;
 for (let i = 1, len = arr.length; i < len; i++) {
 let v = JSON.parse(arr[i]).abilityOrder;
 min = (v < min)? v : min;
 max = (v > max)? v : max;
 }
 return [min, max];
}
var maxAbility = findMinMax(arrayQ);
arrayQ.forEach(function(result, index) {
 result = JSON.parse(result);
 let i = 0;
 if (i <= maxAbility[1] && result.idInteraction) {
 q = q + result.qualification;
 console.log('id..' + result.idInteraction + 'q..' + q);
 q = 0;
 }
});

预期输出结果：

"idInteraction":"{9ae8653e-99ef-11e9-9e08-90c283d38b9a}" - q = 100
"idInteraction":"{8ae8653e-99ef-11e9-9e08-90c283d38b9a}" - q = 50

问题分析 #

你的代码逻辑存在几个关键问题：

• forEach循环里每次累加后立刻把q重置为0，根本没法累加同一个idInteraction的数值
• 基于abilityOrder的最大最小值判断完全没必要，我们的核心需求是按idInteraction分组，和abilityOrder没有关联
• 循环内的let i=0;和i <= maxAbility[1]逻辑无效，因为i每次都是0，这个判断永远成立

解决方案 #

我们可以用一个对象来映射每个idInteraction对应的qualification总和，遍历数组时完成累加，这是最直接高效的方式：

基础实现版本

var arrayQ = [ '{"idInteraction":"{9ae8653e-99ef-11e9-9e08-90c283d38b9a}","abilityOrder":1, "qualification":40}', '{"idInteraction":"{9ae8653e-99ef-11e9-9e08-90c283d38b9a}","abilityOrder":2, "qualification":60}', '{"idInteraction":"{8ae8653e-99ef-11e9-9e08-90c283d38b9a}","abilityOrder":1, "qualification":20}', '{"idInteraction":"{8ae8653e-99ef-11e9-9e08-90c283d38b9a}","abilityOrder":2, "qualification":30}' ];

// 创建空对象存储每个id对应的总和
const qualificationSum = {};

arrayQ.forEach(item => {
  // 解析JSON字符串为JS对象
  const parsedItem = JSON.parse(item);
  const { idInteraction, qualification } = parsedItem;
  
  // 累加逻辑：存在则加，不存在则初始化
  if (qualificationSum[idInteraction]) {
    qualificationSum[idInteraction] += qualification;
  } else {
    qualificationSum[idInteraction] = qualification;
  }
});

// 输出预期格式的结果
for (const id in qualificationSum) {
  console.log(`"idInteraction":"${id}" - q = ${qualificationSum[id]}`);
}

简化版（使用Array.reduce）

如果想让代码更简洁，可以用数组的reduce方法一步完成分组累加：

var arrayQ = [ '{"idInteraction":"{9ae8653e-99ef-11e9-9e08-90c283d38b9a}","abilityOrder":1, "qualification":40}', '{"idInteraction":"{9ae8653e-99ef-11e9-9e08-90c283d38b9a}","abilityOrder":2, "qualification":60}', '{"idInteraction":"{8ae8653e-99ef-11e9-9e08-90c283d38b9a}","abilityOrder":1, "qualification":20}', '{"idInteraction":"{8ae8653e-99ef-11e9-9e08-90c283d38b9a}","abilityOrder":2, "qualification":30}' ];

const qualificationSum = arrayQ.reduce((acc, item) => {
  const { idInteraction, qualification } = JSON.parse(item);
  // 用短路运算符简化判断：如果acc[idInteraction]不存在就取0，再累加
  acc[idInteraction] = (acc[idInteraction] || 0) + qualification;
  return acc;
}, {});

// 遍历结果输出
Object.entries(qualificationSum).forEach(([id, sum]) => {
  console.log(`"idInteraction":"${id}" - q = ${sum}`);
});

运行上述任意版本代码，都会得到你预期的输出结果。

内容的提问来源于stack exchange，提问作者Álvaro Manuel Maraví