javascript - 按多个字段对 Json 数据进行分组

Question

我有一个 JSON 数据，其中包含一些成员(member)作为俱乐部会费支付的付款列表。我正在尝试使用 underscore.js 库对数据进行分组并对数据进行求和。

下面提供了我的示例 JSON 数据。

var dues = [{
    memberid: 194,
    payment: [
      { month: 'January', amount: 2500, year: 2015 },
      { month: 'February', amount: 2500, year: 2015 },
      { month: 'March', amount: 2500, year: 2015 },
      { month: 'April', amount: 2500, year: 2015 },
      { month: 'May', amount: 2500, year: 2015 },
      { month: 'June', amount: 2500, year: 2015 },
      { month: 'July', amount: 2500, year: 2015 },
      { month: 'August', amount: 2500, year: 2015 },
      { month: 'September', amount: 2500, year: 2015 },
      { month: 'October', amount: 2500, year: 2015 },
      { month: 'November', amount: 2500, year: 2015 },
      { month: 'December', amount: 2500, year: 2015 },
      { month: 'March', amount: 2500, year: 2016 },
      { month: 'May', amount: 2500, year: 2016 },
      { month: 'September', amount: 2500, year: 2016 }
    ],
    name: 'Makey Trashey'
  }, {
    memberid: 156,
    payment: [
      { month: 'January', amount: 2500, year: 2015 },
      { month: 'February', amount: 2500, year: 2015 },
      { month: 'March', amount: 2500, year: 2015 },
      { month: 'April', amount: 2500, year: 2015 },
      { month: 'May', amount: 2500, year: 2015 },
      { month: 'June', amount: 2500, year: 2015 },
      { month: 'July', amount: 2500, year: 2015 },
      { month: 'August', amount: 2500, year: 2015 },
      { month: 'September', amount: 2500, year: 2015 },
      { month: 'October', amount: 2500, year: 2015 },
      { month: 'November', amount: 2500, year: 2015 },
      { month: 'December', amount: 2500, year: 2015 },
      { month: 'March', amount: 2500, year: 2016 },
      { month: 'May', amount: 2500, year: 2016 },
      { month: 'July', amount: 2500, year: 2016 }
    ],
    name: 'Makey Johnny'
  }
]

请问，我想按月对支付键数组中的 amount 键求和。

我希望能够按月分组，同时汇总一年中每个月支付的金额。我希望我的数据采用这种格式。

[{
  month: 'January',
  total: 'to be the amount of all amount paid in January'
  year: 1995
}, {
  month: 'February',
  total: 'to be the amount of all amount paid in January'
  year: 1995
}, {
  month: 'March',
  total: 'to be the amount of all amount paid in January'
  year: 1995
}]

感谢您的帮助。

Answer 1

最简单的事情就是创建您自己的分组和哈希函数。

var dues = retrieveData();

var grouped = dues.reduce(function(groupedData, member, index, members) {
  return member.payment.reduce(function(memberData, payment) {
    var key = payment.month + '_' + payment.year;
    if (memberData[key] == null) {
      memberData[key] = {
        month : payment.month,
        total: payment.amount || 0,
        year: payment.year
      };
    } else {
      memberData[key].total += payment.amount; // Update payment.
    }
    return memberData;
  }, groupedData);
}, {});

var valueArr = Object.keys(grouped).map(function(key) {
  return grouped[key];
});

console.log(valueArr);


function retrieveData() {
  return [ {
    memberid: 194,
    payment: [
      { month: 'January', amount: 2500, year: 2015 },
      { month: 'February', amount: 2500, year: 2015 },
      { month: 'March', amount: 2500, year: 2015 },
      { month: 'April', amount: 2500, year: 2015 },
      { month: 'May', amount: 2500, year: 2015 },
      { month: 'June', amount: 2500, year: 2015 },
      { month: 'July', amount: 2500, year: 2015 },
      { month: 'August', amount: 2500, year: 2015 },
      { month: 'September', amount: 2500, year: 2015 },
      { month: 'October', amount: 2500, year: 2015 },
      { month: 'November', amount: 2500, year: 2015 },
      { month: 'December', amount: 2500, year: 2015 },
      { month: 'March', amount: 2500, year: 2016 },
      { month: 'May', amount: 2500, year: 2016 },
      { month: 'September', amount: 2500, year: 2016 }
    ],
    name: 'Makey Trashey'
  }, {
    memberid: 156,
    payment: [
      { month: 'January', amount: 2500, year: 2015 },
      { month: 'February', amount: 2500, year: 2015 },
      { month: 'March', amount: 2500, year: 2015 },
      { month: 'April', amount: 2500, year: 2015 },
      { month: 'May', amount: 2500, year: 2015 },
      { month: 'June', amount: 2500, year: 2015 },
      { month: 'July', amount: 2500, year: 2015 },
      { month: 'August', amount: 2500, year: 2015 },
      { month: 'September', amount: 2500, year: 2015 },
      { month: 'October', amount: 2500, year: 2015 },
      { month: 'November', amount: 2500, year: 2015 },
      { month: 'December', amount: 2500, year: 2015 },
      { month: 'March', amount: 2500, year: 2016 },
      { month: 'May', amount: 2500, year: 2016 },
      { month: 'July', amount: 2500, year: 2016 }
    ],
    name: 'Makey Johnny'
  } ];
};

输出

[
  { "month": "January",    "total": 5000,  "year": 2015 },
  { "month": "February",   "total": 5000,  "year": 2015 },
  { "month": "March",      "total": 5000,  "year": 2015 },
  { "month": "April",      "total": 5000,  "year": 2015 },
  { "month": "May",        "total": 5000,  "year": 2015 },
  { "month": "June",       "total": 5000,  "year": 2015 },
  { "month": "July",       "total": 5000,  "year": 2015 },
  { "month": "August",     "total": 5000,  "year": 2015 },
  { "month": "September",  "total": 5000,  "year": 2015 },
  { "month": "October",    "total": 5000,  "year": 2015 },
  { "month": "November",   "total": 5000,  "year": 2015 },
  { "month": "December",   "total": 5000,  "year": 2015 },
  { "month": "March",      "total": 5000,  "year": 2016 },
  { "month": "May",        "total": 5000,  "year": 2016 },
  { "month": "September",  "total": 2500,  "year": 2016 },
  { "month": "July",       "total": 2500,  "year": 2016 }
]

<小时/>

通用方法

下面，我将数据与上面的代码解耦，并将逻辑放入其自己的函数中。它远非完美，但它是一个开始。

var dues = retrieveData();
var valueArr = groupData(dues, 'payment', ['month', 'year'], 'amount', 'total');

console.log(valueArr);

function groupData(data, targetProp, keys, accumFrom, accumTo) {
  var grouped = data.reduce(function(groupedData, item, index, items) {
    return item[targetProp].reduce(function(obj, record) {
      var key = keys.map(function(key) { return record[key]; }).join('_');
      if (obj[key] == null) {
        obj[key] = keys.reduce(function(data, key) {
          data[key] = record[key];
          return data;
        }, {});
      }
      obj[key][accumTo] = (obj[key][accumTo] || 0) + record[accumFrom];
      return obj;
    }, groupedData);
  }, {});

  return Object.keys(grouped).map(function(key) {
    return grouped[key];
  });
}

function retrieveData() {
  return [ {
    memberid: 194,
    payment: [
      { month: 'January', amount: 2500, year: 2015 },
      { month: 'February', amount: 2500, year: 2015 },
      { month: 'March', amount: 2500, year: 2015 },
      { month: 'April', amount: 2500, year: 2015 },
      { month: 'May', amount: 2500, year: 2015 },
      { month: 'June', amount: 2500, year: 2015 },
      { month: 'July', amount: 2500, year: 2015 },
      { month: 'August', amount: 2500, year: 2015 },
      { month: 'September', amount: 2500, year: 2015 },
      { month: 'October', amount: 2500, year: 2015 },
      { month: 'November', amount: 2500, year: 2015 },
      { month: 'December', amount: 2500, year: 2015 },
      { month: 'March', amount: 2500, year: 2016 },
      { month: 'May', amount: 2500, year: 2016 },
      { month: 'September', amount: 2500, year: 2016 }
    ],
    name: 'Makey Trashey'
  }, {
    memberid: 156,
    payment: [
      { month: 'January', amount: 2500, year: 2015 },
      { month: 'February', amount: 2500, year: 2015 },
      { month: 'March', amount: 2500, year: 2015 },
      { month: 'April', amount: 2500, year: 2015 },
      { month: 'May', amount: 2500, year: 2015 },
      { month: 'June', amount: 2500, year: 2015 },
      { month: 'July', amount: 2500, year: 2015 },
      { month: 'August', amount: 2500, year: 2015 },
      { month: 'September', amount: 2500, year: 2015 },
      { month: 'October', amount: 2500, year: 2015 },
      { month: 'November', amount: 2500, year: 2015 },
      { month: 'December', amount: 2500, year: 2015 },
      { month: 'March', amount: 2500, year: 2016 },
      { month: 'May', amount: 2500, year: 2016 },
      { month: 'July', amount: 2500, year: 2016 }
    ],
    name: 'Makey Johnny'
  } ];
};