聚合
执行任何类型的所需的聚合,并允许在创建自定义LINQ聚合。
操作 | 描述 | C#查询表达式语法 | VB查询表达式语法 |
---|---|---|---|
Aggregate | 对集合的值进行操作执行自定义聚合操作 | 不适用 | 不适用 |
Average | 计算集合的平均值 | 不适用 | Aggregate … In … Into Average() |
Count | 计算在收集谓词功能的元素 | 不适用 | Aggregate … In … Into Count() |
LonCount | 计算一个巨大的集合中满足谓词函数的元素 | 不适用 | Aggregate … In … Into LongCount() |
Max | 找出一个集合中的最大值 | 不适用 | Aggregate … In … Into Max() |
Min | 找出一个集合中的最小值 | 不适用 | Aggregate … In … Into Min() |
Sum | 计算一个集合中的值的总和 | 不适用 | Aggregate … In … Into Sum() |
示例
VB
Module Module1 Sub Main() Dim num As Integer() = {1, 2, 3, 4, 5, 6, 7, 8, 9} Dim intDivByTwo = Aggregate n In num Where n > 6 Into Count() Console.WriteLine("Count of Numbers: " & intDivByTwo) Dim intResult = Aggregate n In num Where n > 6 Into Average() Console.WriteLine("Average of Numbers: " & intResult) intResult = Aggregate n In num Where n > 6 Into LongCount() Console.WriteLine("Long Count of Numbers: " & intResult) intResult = Aggregate n In num Into Max() Console.WriteLine("Max of Numbers: " & intResult) intResult = Aggregate n In num Into Min() Console.WriteLine("Min of Numbers: " & intResult) intResult = Aggregate n In num Into Sum() Console.WriteLine("Sum of Numbers: " & intResult) Console.ReadLine() End Sub End Module
当上述的VB代码被编译和执行时,它产生了以下结果:
Count of Numbers: 3 Average of Numbers: 8 Long Count of Numbers: 3 Max of Numbers: 9 Min of Numbers: 1 Sum of Numbers: 45