我有一个JSON数据，其中包含一些成员作为俱乐部会费的付款清单。我正在尝试使用 underscore.js 库对数据进行分组，并总结数据。
我的示例JSON数据在下面提供。
[{
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
}]
请，我想按月汇总付款密钥数组中的金额总额。
我希望能够按月分组，同时汇总一年中每个月支付的金额。我想要这种格式的数据。
CREATE TABLE t1 (
id serial PRIMARY KEY,
name text
);
CREATE TABLE t2 (
id serial PRIMARY KEY,
name text,
foo text
);
CREATE FUNCTION gen_t2_foo(_a t1, _b t2) RETURNS text AS $$
SELECT _a.name || ' - ' || _b.name;
$$ LANGUAGE sql;
CREATE FUNCTION upd_t2(_min_id int, _max_id int, _a t1) RETURNS VOID AS $$
UPDATE t2 SET
foo = gen_f2_name(_a, ???) -- How to pass the current t2 record?
WHERE id >= _min_id AND id <= _max_id;
$$ LANGUAGE sql;
感谢您提供帮助。
答案 0 :(得分：2)
最简单的方法是创建自己的分组和散列函数。
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'
} ];
};
[
{ "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 }
]
下面，我将数据与上面的代码分离，并将逻辑放入自己的函数中。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'
} ];
};
答案 1 :(得分：0)
由于问题标有下划线：
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'}];
// Get all the payments from each members & flatten it to a 1-d array
var grouped = _.chain(dues).pluck('payment').flatten().groupBy(function (payment) {
return [payment.month, payment.year].join('_'); // group payments with month+year as the grouping key
}).map(function (monthlyPayments) {
// Calculate total for each group
var totalMonthlyPayment = _.reduce(monthlyPayments, function (memo, payment) {
return payment.amount + memo;
}, 0);
return {month: monthlyPayments[0].month, year: monthlyPayments[0].year, total: totalMonthlyPayment};
}).value();
console.log(grouped);<script src="http://underscorejs.org/underscore-min.js"></script>