C＃Linq平均值

我有一个表格，数据类似于下面：

Group TimePoint Value 1 0 1 1 0 2 1 0 3 1 1 3 1 1 5 

我想像这样投影一个表：

 Group TimePoint AverageValue 1 0 2 1 1 4 

编辑：数据在数据表中。

任何人有任何想法如何使用LINQ或其他方式完成此操作？

谢谢。

Answer 1

您需要执行分组依据

你需要的linq是这样的：

 var query = from item in inputTable group item by new { Group = item.Group, TimePoint = item.TimePoint } into grouped select new { Group = grouped.Key.Group, TimePoint = grouped.Key.TimePoint, AverageValue = grouped.Average(x => x.Value) } ; 

有关更多Linq示例，我强烈推荐101 Linq示例页面 – http://msdn.microsoft.com/en-us/vcsharp/aa336747#avgGrouped

Answer 2

这是一种更注重function的方法（我更喜欢它）。 第一行不会编译，所以请用您的数据填写。

 var items = new[] { new { Group = 1, TimePoint = 0, Value = 1} ... }; var answer = items.GroupBy(x => new { TimePoint = x.TimePoint, Group = x.Group }) .Select(x => new { Group = x.Key.Group, TimePoint = x.Key.TimePoint, AverageValue = x.Average(y => y.Value), } ); 

Answer 3

你可以做：

 IEnumerable table = ... var query = from item in table group item by new { item.Group, item.TimePoint } into g select new { g.Key.Group, g.Key.TimePoint, AverageValue = g.Average(i => i.Value) }; 

Answer 4

假设这样一个类：

 public class Record { public int Group {get;set;} public int TimePoint {get;set;} public int Value {get;set;} } var groupAverage = from r in records group r by new { r.Group, r.TimePoint } into groups select new { Group = groups.Key.Group, TimePoint = groups.Key.TimePoint, AverageValue = groups.Average(rec => rec.Value) };