c# - 如何在 C# 中执行多级聚合？

Question

我有以下收藏

PaymentStatus   Amount  Receipt
-------------   ------  ---------
Status1         450     123
Status1         54      777
Status2         1230    234
Status2         67      12
Status3         3452    235
Status3         11111   678
Status4         678     156
Status5         346     12
Status5         1000    7
Status6         2000    753

我需要以这样的方式执行分组，以便结果集如下

CollectionUnit  MoneyCollected  NoOfReceipt
--------------- --------------  -------------
Unit1               504             2
Unit2               15860           4
Unit3               678             1
Unit4               3346            3

CollectionUnit的定义

Unit1 who falls in the Status1
Unit2 who falls in the Status2 and Status3
Unit3 who falls in the Status4
Unit4 who falls in the Status5 and Status6

MoneyCollected = Sum(Amount)

NoOfReceipt = 计数(收据)

我已经能够执行第一级聚合

using System;
using System.Collections.Generic;
using System.Linq;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {  

           var paymentCollections = new List<Payment>() {
                new Payment { PaymentStatus= "Status1", Amount=450, Receipt=123 },
                new Payment { PaymentStatus= "Status1", Amount=54, Receipt=777 },
                new Payment { PaymentStatus= "Status2", Amount=1230, Receipt=234 },
                 new Payment { PaymentStatus= "Status2", Amount=67, Receipt=12 },
                 new Payment { PaymentStatus= "Status3", Amount=3452, Receipt=235 },
                new Payment { PaymentStatus= "Status3", Amount=11111, Receipt=678 },
                new Payment { PaymentStatus= "Status4", Amount=678, Receipt=156 },
                 new Payment { PaymentStatus= "Status5", Amount=346, Receipt=12 },
                  new Payment { PaymentStatus= "Status5", Amount=1000, Receipt=7 },
                   new Payment { PaymentStatus= "Status6", Amount=2000, Receipt=753 }
            };

            //level 1 aggregation
            var result = paymentCollections.GroupBy(l => l.PaymentStatus)
                        .Select(cl => new MoneyMovement
                        {
                            CollectionUnit = cl.First().PaymentStatus,
                            MoneyCollected = cl.Sum(c => c.Amount).ToString(),
                            NoOfReceipt = cl.Count().ToString(),
                        }).ToList();
            Console.ReadKey();
        }
    }

    public class Payment
    {
        public string PaymentStatus { get; set; }
        public float Amount { get; set; }
        public int Receipt { get; set; }
    }

    public class MoneyMovement
    {
        public string CollectionUnit { get; set; }

        public string MoneyCollected { get; set; }

        public string NoOfReceipt { get; set; }
    }
}

Answer 1

您可以按条件分组。即:

//level 1 aggregation
var result = paymentCollections
            .GroupBy(l => new
            {
                Unit = l.PaymentStatus == "Status1"
                ? "Unit1"
                : l.PaymentStatus == "Status2" || l.PaymentStatus == "Status3"
                ? "Unit2"
                : l.PaymentStatus == "Status4"
                ? "Unit3"
                : l.PaymentStatus == "Status5" || l.PaymentStatus == "Status6"
                ? "Unit4"
                : "Unknown"
            })
            .Select(cl => new MoneyMovement
            {
                CollectionUnit = cl.Key.Unit,
                MoneyCollected = cl.Sum(c => c.Amount).ToString(),
                NoOfReceipt = cl.Count().ToString(),
            }).ToList();