C# 求和的平均值

示例集合：

List<Product> list = new List<Product>();
list.Add(new Product { Id = 1, Good = 50, Total = 50 });
list.Add(new Product { Id = 2, Good = 18, Total = 30 });
list.Add(new Product { Id = 2, Good = 15, Total = 30 });
list.Add(new Product { Id = 1, Good = 40, Total = 50 });
list.Add(new Product { Id = 3, Good = 6, Total = 10 });
list.Add(new Product { Id = 1, Good = 45, Total = 50 });
list.Add(new Product { Id = 3, Good = 8, Total = 10 });

我只对Linq解决方案感兴趣。

类似的东西

var groups = list.GroupBy(l => l.Id)
                 .Select(g => new {
                                      Id = g.Key, 
                                      GoodSum = g.Sum(i=>i.Good), 
                                      TotalSum= g.Sum(i=>i.Total),
                                      Perc = (double) g.Sum(i=>i.Good) / g.Sum(i=>i.Total)
                                  }
                        );

 var average = groups.Average(g=>g.Perc);

请注意，

Avg

的答案应该是

0.717

而不是

7.17

类似的答案

var groups = list.GroupBy(l => l.Id)
                 .Select(g => new {
                                      Id = g.Key, 
                                      GoodSum = g.Sum(i=>i.Good), 
                                      TotalSum= g.Sum(i=>i.Total),
                                      Perc = (double) g.Sum(i=>i.Good) / g.Sum(i=>i.Total)
                                  }
                        );

 var average = groups.Average(g=>g.Perc);

请注意，

Avg

的答案应该是

0.717

而不是

7.17

尝试以下方法：

var avg = list.GroupBy(G => G.Id)
              .Select(G => (G.Sum(T => T.Good)/G.Sum(T => T.TotalSum)))
              .Average();

试试这个：

var avg = list.GroupBy(G => G.Id)
              .Select(G => (G.Sum(T => T.Good)/G.Sum(T => T.TotalSum)))
              .Average();