根据键c＃合并两个列表

我有课程奖励，我保持每场比赛的用户资金。 我有两个列表，我需要联系。 我在下面写下样本列表和所需的结果。

public class Reward { public int Game { get; set; } public int User { get; set; } public int Money { get; set; } public Reward Merge(Reward p) { return new Reward { Game = this.Game, User = this.User, Money = this.Money + p.Money}; } } IList list1 = new List(); list1.Add(new Reward {Game = 1, User = 1, Money = 10}); list1.Add(new Reward { Game = 1, User = 2, Money = 20 }); list1.Add(new Reward { Game = 1, User = 3, Money = 30 }); IList list2 = new List(); list2.Add(new Reward { Game = 2, User = 1, Money = 15 }); list2.Add(new Reward { Game = 2, User = 2, Money = 25 }); list2.Add(new Reward { Game = 2, User = 4, Money = 35 }); 

结果列表应该是

 User Money 1 25 2 45 3 30 4 35 

我试试

 IList listConcat = list1.Concat(list2) .GroupBy(u=> u.User) .Select(???) .ToList(); 

但是怎么样？

Answer 1

你在GroupBy的正确轨道上，这应该做的工作：

 IEnumerable result = from r in list1.Concat(list2) group r by r.User into groupedRewards select new Reward { Game = 0, //what game to use? User = groupedRewards.Key, Money = groupedRewards.Sum(r => r.Money) }; 

编辑 ：与lambda表达式相同：

 IEnumerable result = list1.Concat(list2) .GroupBy(u => u.User) .Select(g => new Reward { Game = 0, //what game to use? User = g.Key, Money = g.Sum(r => r.Money) }); 

Answer 2

这不是很漂亮，但它确实有效。

 var listConcat = list1.Concat(list2) .GroupBy(u=> u.User) .Select(rewards => new Reward { User = rewards.Key, Money = rewards.Select(reward => reward.Money).Sum() } ) .ToList(); 

Answer 3

使用.GroupBy ，您将获得一个IGrouping列表，因此select就像这样：

 IEnumerable listConcat = list1.Concat(list2) .GroupBy(x => x.User) .Select(x => new Reward { User= x.Key, Money=x.Sum(y => y.Money) }); 

Answer 4

我想一个接近你正在寻找的答案看起来像这样：

 var catList = list1.Concat(list2) .GroupBy (x => x.User) .Select (y => new Reward{Game = 0, Money = y.Sum (z => z.Money), User = y.Key}) .ToList(); 

至于使用哪种游戏，您可以考虑匿名选择（即

 .Select(new {Money = y.Sum (z => z.Money), User = y.Key}) 

这将为您提供一个匿名类型，其中包含您要使用的信息。 但是，如果要将其从方法中删除，最佳做法是给它一个类型，或者只是理解游戏0是你所有游戏的超集。

Answer 5

 IList listConcat = list1.Concat(list2) .GroupBy(person => person.User) .Select(group => group.Aggregate((rewardone, rewardtwo) => rewardone.Merge(rewardtwo))) .ToList(); 

Answer 6

请更改行：

  return new Reward { Game = this.Game, User = this.User, Money = this.Money + p.User 

至

  return new Reward { Game = this.Game, User = this.User, Money = this.Money + p.Money