LINQ 中的聚合
执行任何类型的所需聚合并允许在 LINQ 中创建自定义聚合。
| 运算符 | 描述 | C# 查询表达式语法 | VB 查询表达式语法 |
|---|---|---|---|
| 聚合 | 对集合的值进行操作以执行自定义聚合操作 | 不适用 | 不适用 |
| 平均值 | 平均值计算一组值的值 | 不适用 | Aggregate … In … Into Average() |
| Count | 计算集合中满足谓词函数的元素 | 不适用 | Aggregate … In … Into Count() |
| LonCount | 计算大型集合中满足谓词函数的元素 | 不适用 | Aggregate … In … Into LongCount() |
| Max | 找出集合中的最大值 | 不适用适用 | Aggregate … In … Into Max() |
| Min | 找出集合中存在的最小值 | 不适用 | Aggregate … In … Into Min() |
| Sum | 找出集合中值的总和 | 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
当编译并执行上述 VB 代码时，它会产生以下结果 −
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
linq_query_operators.html
