如何高效统计JavaScript数组中班次与部门的关联数量

嘿，作为JavaScript新手真的不用把这个问题想复杂！我给你准备了一个简单易懂的方案，既能统计每个班次的总人数，也能统计「班次+部门」组合的人数，完全贴合你想要的输出格式～

核心思路 #

我们可以用一个对象来存储所有统计结果，遍历你的数据数组时，分别更新单独班次和班次+部门组合的计数，最后把统计对象转换成你需要的字符串格式就行。

代码实现 #

// 你的原始数据数组
const data = [
  {"shift":2,"department":"Pallet-Pack"},
  {"shift":1,"department":"Carton-Pack"},
  {"shift":2,"department":"Carton-Pack"},
  {"shift":1,"department":"Picking"},
  {"shift":1,"department":"Carton-Pack"},
  {"shift":1,"department":"Carton-Pack"},
  {"shift":2,"department":"Picking"},
  {"shift":3,"department":"Inventory"},
  {"shift":1,"department":"Carton-Pack"},
  {"shift":1,"department":"Receiving"},
  {"shift":3,"department":"Equipment"},
  {"shift":2,"department":"Receiving"},
  {"shift":1,"department":"Picking"},
  {"shift":1,"department":"Picking"},
  {"shift":2,"department":"Carton-Pack"},
  {"shift":2,"department":"Carton-Pack"},
  {"shift":1,"department":"Receiving"},
  {"shift":1,"department":"Returns"},
  {"shift":1,"department":"Receiving"},
  {"shift":1,"department":"Picking"},
  {"shift":2,"department":"Receiving"},
  {"shift":1,"department":"Pallet-Pack"},
  {"shift":2,"department":"Picking"},
  {"shift":1,"department":"Carton-Pack"}
];

// 用reduce方法统计数据
const stats = data.reduce((acc, item) => {
  // 统计单独班次的数量
  const shiftKey = `shift ${item.shift}`;
  acc[shiftKey] = (acc[shiftKey] || 0) + 1;

  // 统计班次+部门组合的数量
  const comboKey = `shift ${item.shift} & ${item.department}`;
  acc[comboKey] = (acc[comboKey] || 0) + 1;

  return acc;
}, {});

// 转换成你想要的字符串格式
const result = Object.entries(stats).map(([key, value]) => `${key}: ${value}`).join(' ');

console.log(result);

代码解释 #

• reduce方法：这是JavaScript里专门做累加/聚合操作的工具，比手动写for循环更简洁，逻辑也更清晰。我们用它遍历整个数据数组，逐步构建统计对象。
• 统计键的生成：
  • 单独班次的键是shift X（比如shift 1）
  • 组合键是shift X & 部门名称（比如shift 1 & Carton-Pack）
• 计数更新：acc[key] = (acc[key] || 0) + 1这句话的意思是，如果统计对象里还没有这个键，就从0开始加1；如果已经有了，就在原来的数字上加1。
• 格式转换：最后用Object.entries把统计对象转成键值对数组，再用map把每一组转成key: value的字符串，最后用空格连接起来，就得到了你想要的输出格式。

运行结果 #

运行这段代码后，你会得到类似这样的输出：

shift 2: 9 shift 2 & Pallet-Pack: 1 shift 1: 13 shift 1 & Carton-Pack: 6 shift 1 & Picking: 4 shift 1 & Receiving: 3 shift 1 & Returns: 1 shift 1 & Pallet-Pack: 1 shift 2 & Carton-Pack: 3 shift 2 & Picking: 2 shift 2 & Receiving: 2 shift 3: 2 shift 3 & Inventory: 1 shift 3 & Equipment: 1

完全符合你想要的统计需求，而且代码简单易读，新手也能轻松理解～

内容的提问来源于stack exchange，提问作者Gabriel Motta