Linq Groupby進行分類，但是如何操作集合中的值

Question

我有一個可觀察的集合Auctions，它是Type Auction，看起來像

public class Auction
{
     public int GroupId {get; set;}
     public DateTime Date {get; set;}
     public string Hour {get; set;}
     public decimal Offer {get; set;}
     public decimal Bid {get; set;}
     public decimal OfferPrice {get; set;}
     public decimal BidPrice {get; set;}
}

該集合包含以下數據，

Group Id    Date    Hour    Offer   Bid Offer Price Bid Price
1   27/06/2013  00:00   5.556   86.3    250 0
1   27/06/2013  00:15   0   0   250 0
1   27/06/2013  00:30   0   0   250 0
1   27/06/2013  00:45   0   0   250 0
1   27/06/2013  01:00   0   0   250 0
1   27/06/2013  01:15   5.556   86.3    250 0
2   27/06/2013  01:30   8.68    19.9    100 20
2   27/06/2013  01:45   0   0   100 20
2   27/06/2013  02:00   8.68    19.9    100 20
2   27/06/2013  02:15   0   0   100 20
2   27/06/2013  02:30   8.68    19.9    100 20
2   27/06/2013  02:45   0   0   100 20
2   27/06/2013  03:00   8.68    19.9    100 20
3   27/06/2013  03:15   87.14   87.1    150 0
3   27/06/2013  03:30   0   0   150 0
3   27/06/2013  03:45   0   0   150 0
3   27/06/2013  04:00   0   0   150 0
3   27/06/2013  04:15   0   0   150 0
3   27/06/2013  04:30   0   0   150 0
3   27/06/2013  04:45   0   0   150 0
3   27/06/2013  05:00   0   0   150 0

現在我想做的是

• 通過GroupId進行分組收集，因此我得到3個塊，其中GroupId = 1，GroupId = 2和GroupId = 3。
• 然后，我需要將不在組1中的所有內容都設置為零，並將其添加到組1中。

例，

• 將原樣復制綠色組1的所有內容，然后在組1后面附加其余數據，但將其設置為零。
• 對於組2和組3同樣。

通過Linq做到這一點的最佳方法是什么？

需要添加結果的集合是BOD類型，並且包含

Public class BOD
{
    public DateTime Date {get; set;}
    public string Time {get; set;}
    public decimal Volume {get; set;}
    public decimal Price {get; set;}
}

Answer 1

您可以嘗試類似的方法：

var list = new List<YourType>(); // Your data source
var groupedList = list.GroupBy(listEntry => listEntry.GroupId);

foreach(var groupList in groupedList)
{
   var unionList = groupList.ToList()
       .Union(list.Where(listEntry => listEntry.GroupId != groupList.Key)
       .Select(listEntry => new YourType { GroupId = groupList.Key, a = 0, b = 0, c = listEntry.c }))
}

Answer 2

您可以將拍賣列表加入到唯一的GroupId列表中：

var q = (from a in Auctions
         from g in (Auctions.Select(aa=>aa.GroupId).Distinct())
         orderby g, a.Date, a.Hour
         select new Auction
             {
                  GroupId = g,
                  Date = a.Date,
                  Hour = a.Hour,
                  Offer      = a.GroupId == g ? a.Offer : 0,
                  Bid        = a.GroupId == g ? a.Bid : 0,
                  OfferPrice = a.GroupId == g ? a.OfferPrice : 0,
                  BidPrice   = a.GroupId == g ? a.BidPrice : 0
              }

Answer 3

這樣的事情應該起作用：

var group1 =
            (from a in auctions where a.GroupId == 1 select a).Union(
                from a in auctions
                where a.GroupId != 1
                select new Auction { GroupId = 1, Date = a.Date, Hour = a.Hour });

除非您特意復制它們，否則新的拍賣將包含零。 您希望擺脫硬編碼的ID，但這並不難解決。

Answer 4

我不確定添加其他組中的項目是否正確，但請查看以下查詢：

var auctions = new List<Auction>
{
    new Auction {GroupId = 1, Date = DateTime.Parse("27/06/2013"), Hour = "00:00", Offer = 5.556m, Bid = 86.3m, OfferPrice = 250m, BidPrice = 0m},
    new Auction {GroupId = 1, Date = DateTime.Parse("27/06/2013"), Hour = "00:15", Offer = 0m, Bid = 0m, OfferPrice = 250m, BidPrice = 0m},
    new Auction {GroupId = 1, Date = DateTime.Parse("27/06/2013"), Hour = "00:30", Offer = 0m, Bid = 0m, OfferPrice = 250m, BidPrice = 0m},
    new Auction {GroupId = 1, Date = DateTime.Parse("27/06/2013"), Hour = "00:45", Offer = 0m, Bid = 0m, OfferPrice = 250m, BidPrice = 0m},
    new Auction {GroupId = 1, Date = DateTime.Parse("27/06/2013"), Hour = "01:00", Offer = 0m, Bid = 0m, OfferPrice = 250m, BidPrice = 0m},
    new Auction {GroupId = 1, Date = DateTime.Parse("27/06/2013"), Hour = "01:15", Offer = 5.556m, Bid = 86.3m, OfferPrice = 250m, BidPrice = 0m},
    new Auction {GroupId = 2, Date = DateTime.Parse("27/06/2013"), Hour = "01:30", Offer = 8.68m, Bid = 19.9m, OfferPrice = 100m, BidPrice = 20m},
    new Auction {GroupId = 2, Date = DateTime.Parse("27/06/2013"), Hour = "01:45", Offer = 0m, Bid = 0m, OfferPrice = 250m, BidPrice = 20m},
    new Auction {GroupId = 2, Date = DateTime.Parse("27/06/2013"), Hour = "02:00", Offer = 8.68m, Bid = 19.9m, OfferPrice = 100m, BidPrice = 20m},
    new Auction {GroupId = 2, Date = DateTime.Parse("27/06/2013"), Hour = "02:15", Offer = 0m, Bid = 0m, OfferPrice = 100m, BidPrice = 20m},
    new Auction {GroupId = 2, Date = DateTime.Parse("27/06/2013"), Hour = "02:30", Offer = 8.68m, Bid = 19.9m, OfferPrice = 100m, BidPrice = 20m},
    new Auction {GroupId = 2, Date = DateTime.Parse("27/06/2013"), Hour = "02:45", Offer = 0m, Bid = 0m, OfferPrice = 100m, BidPrice = 20m},
    new Auction {GroupId = 2, Date = DateTime.Parse("27/06/2013"), Hour = "03:00", Offer = 8.68m, Bid = 19.9m, OfferPrice = 100m, BidPrice = 20m},
    new Auction {GroupId = 3, Date = DateTime.Parse("27/06/2013"), Hour = "03:15", Offer = 87.14m, Bid = 87.1m, OfferPrice = 150m, BidPrice = 0m},
    new Auction {GroupId = 3, Date = DateTime.Parse("27/06/2013"), Hour = "03:30", Offer = 0m, Bid = 0m, OfferPrice = 150m, BidPrice = 0m},
    new Auction {GroupId = 3, Date = DateTime.Parse("27/06/2013"), Hour = "03:45", Offer = 0m, Bid = 0m, OfferPrice = 150m, BidPrice = 0m},
    new Auction {GroupId = 3, Date = DateTime.Parse("27/06/2013"), Hour = "04:00", Offer = 0m, Bid = 0m, OfferPrice = 150m, BidPrice = 0m},
    new Auction {GroupId = 3, Date = DateTime.Parse("27/06/2013"), Hour = "04:15", Offer = 0m, Bid = 0m, OfferPrice = 150m, BidPrice = 0m},
    new Auction {GroupId = 3, Date = DateTime.Parse("27/06/2013"), Hour = "04:30", Offer = 0m, Bid = 0m, OfferPrice = 150m, BidPrice = 0m},
    new Auction {GroupId = 3, Date = DateTime.Parse("27/06/2013"), Hour = "04:45", Offer = 0m, Bid = 0m, OfferPrice = 150m, BidPrice = 0m},
    new Auction {GroupId = 3, Date = DateTime.Parse("27/06/2013"), Hour = "05:00", Offer = 0m, Bid = 0m, OfferPrice = 150m, BidPrice = 0m}
};

// Create 2 BOD object for each Auction
var b1 =
        from a in auctions
        from b in new List<BOD> {
                new BOD { Date = a.Date, Time = a.Hour, Price = a.BidPrice, Volume = a.Bid },
                new BOD { Date = a.Date, Time = a.Hour, Price = a.OfferPrice, Volume = a.Offer } 
        }
        select b;

// Create 2 BOD object with zero price and volume for each Auction with another GroupId
var b2 =
        from d in auctions.Select(x => x.GroupId)
        from a in auctions.Where(y => y.GroupId != d)
        from b in new List<BOD> {
                new BOD { Date = a.Date, Time = a.Hour, Price = 0, Volume = 0 },
                new BOD { Date = a.Date, Time = a.Hour, Price = 0, Volume = 0 } 
        }
        select b;

var bods = b1.Union(b2);