c# - 按月将一个列表拆分为多个 - C#、Linq

Question

我有以下 Linq 查询:

List<MonthlySales> monthlySales = (from sale in Sales
                     group sale by new { sale.DateSold.Month, sale.Product.Shop } into ds
                     select new MonthlyTitleSales
                     {
                         Shop = ds.Select(it => it.Product.Shop).FirstOrDefault(),
                         Month = ds.Select(it => it.DateSold.Month).FirstOrDefault(),
                         Year = ds.Select(it => it.DateSold.Year).FirstOrDefault(),
                         USDNumberItemsSold = ds.Where(it => it.USDCut.HasValue).Where(it => it.USDCut != 0).Count(),
                         GBPNumberItemsSold = ds.Where(it => it.GBPCut.HasValue).Where(it => it.GBPCut != 0).Count(),
                         EURNumberItemsSold = ds.Where(it => it.EURCut.HasValue).Where(it => it.EURCut != 0).Count(),
                         USDRevenueTotal = PerformCurrencyConversion(ds.Sum(it => it.USDCut.HasValue ? it.USDCut.Value : 0), 0M, 0M, Currency, endDate),
                         GBPRevenueTotal = PerformCurrencyConversion(0M, ds.Sum(it => it.GBPCut.HasValue ? it.GBPCut.Value : 0), 0M, Currency, endDate),
                         EURRevenueTotal = PerformCurrencyConversion(0M, 0M, ds.Sum(it => it.EURCut.HasValue ? it.EURCut.Value : 0), Currency, endDate),
                     }).OrderBy(it => it.DateSold.Month).ToList();

此查询为我提供了一个列表，每个列表项中包含以下元素:商店、月、年、收入

我最终需要做的是计算每个月所有商店的收入中位数，因此我需要以允许我这样做的方式准备好数据。

我认为一种方法可能是按月将此列表分成小列表，但我怀疑这是最有效的解决方案。

有没有人对此有任何想法？

任何需要查看的人的每月销售类(class):

public class MonthlySales
    {
        public int Month { get; set; }
        public int Year { get; set; }

        public Shop Shop { get; set; }

        public int USDNumberItemsSold { get; set; }
        public int GBPNumberItemsSold { get; set; }
        public int EURNumberItemsSold { get; set; }
        public int TotalNumberItemsSold { get { return USDNumberItemsSold + GBPNumberItemsSold + EURNumberItemsSold; } }

        public decimal USDRevenueTotal { get; set; }
        public decimal GBPRevenueTotal { get; set; }
        public decimal EURRevenueTotal { get; set; }
        public decimal OverallEarnings { get { return USDRevenueTotal + GBPRevenueTotal + EURRevenueTotal; } }
    }

Answer 1

您可以使用 GroupBy 将列表按月分组。例如，以下将按月(实际上是月+年)分组，然后每月将所有值写入控制台:

var grouped = monthlySales.GroupBy(ms => string.Format("{0}-{1}", ms.Month, ms.Year));

foreach(var group in grouped)
{
     Console.WriteLine("Values in month-year of {0}:", group.Key);
     foreach(var ms in group)
         Console.WriteLine("   {0}", ms.USDRevenueTotal);
}