聚合运算符,用于分析查询结果,而且不必迭代索引结果
Count():结果个数
Min():最小值
Max():最大值
Average():平均值
Sum():总和
示例代码:使用聚合运算符分析大数据查询结果
using static System.Console;
- static void Main(string[] args)
- {
- int[] numbers = generateLotsOfNumbers(12345678);
- WriteLine("Numeric Aggregates");
- var queryResults =
- from n in numbers
- where n > 1000
- select n
- ;
- WriteLine("Count of Numbers > 1000");
- WriteLine(queryResults.Count());
- WriteLine("Max of Numbers > 1000");
- WriteLine(queryResults.Max());
- WriteLine("Min of Numbers > 1000");
- WriteLine(queryResults.Min());
- WriteLine("Average of Numbers > 1000");
- WriteLine(queryResults.Average());
- WriteLine("Sum of Numbers > 1000");
- WriteLine(queryResults.Sum(n => (long)n));
- }
- private static int[] generateLotsOfNumbers(int count)
- {
- Random generator = new Random(0);
- int[] result = new int[count];
- for (int i = 0; i < count; i++)
- {
- result[i] = generator.Next();
- }
- return result;
- }