c# - 如何按日期时间对字典进行分组并对 int 求和

Question

我有这段代码:

    var tradeReqsBySegment = segGroups.Join(pPeriods, s => s.MarketSegmentId, p => p.EntityId, (s, p) => new
    {
        SegmentCode = s.SegmentCode, // string
        Time = p.StartLocal, // datetime
        TradeRequirement = p.Volume // double
    })
    .GroupBy(s => s.SegmentCode)
    .ToDictionary(g => g.Key, g => g.ToDictionary(i => i.Time, i=>i.TradeRequirement));

我希望 g.ToDictionary(i => i.Time, i=>i.TradeRequirement)) 按时间分组，TradeRequirement求和或平均。我该如何处理？

此外，是否可以按月对时间进行分组，例如 get :

Time - TradeReq
01/2013 - 500
02/2013 - 234
...

Answer 1

g.GroupBy(gr => new DateTime(gr.Time.Year, gr.Time.Month, 1))
         .ToDictionary(i => i.Key, i => i.Sum(s => s.TradeRequirement));