C# Linq排序

今天在家看了一下linq，实践了一下书中代码，发现排序和查重的先后顺序太重要了。

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 
 6 namespace LinqLearning
 7 {
 8     class Program
 9     {
10         private static int[] GenerateLotsOfNumbers(int count)
11         {
12             Random generator = new Random(0);
13             int[] result = new int[count];
14             for (int i = 0; i < count; i++)
15             {
16                 result[i] = generator.Next();
17             }
18             return result;
19         }
20 
21         static void Main(string[] args)
22         {
23             int[] numbers = GenerateLotsOfNumbers(12345678);
24 
25             var queryResults = from n in numbers
26                                where n < 1000
27                                orderby n descending
28                                select n;
29             Console.WriteLine("查询语法排序结果：");
30             DateTime start = DateTime.Now;
31             foreach (var item in queryResults)
32                 Console.WriteLine(item);
33             Console.WriteLine("消耗时间：{0}",DateTime.Now-start);
34 
35             var queryResult = numbers.OrderByDescending(n => n).Where(n => n < 1000);
36             Console.WriteLine("方法排序结果（排序字段在前）：");
37             start = DateTime.Now;
38             foreach (var item in queryResult)
39                 Console.WriteLine(item);
40             Console.WriteLine("消耗时间：{0}", DateTime.Now - start);
41 
42             var query = numbers.Where(n => n < 1000).OrderByDescending(n => n);
43             Console.WriteLine("方法排序结果（排序字段在后）：");
44             start = DateTime.Now;
45             foreach (var item in query)
46                 Console.WriteLine(item);
47             Console.WriteLine("消耗时间：{0}", DateTime.Now - start);
48 
49             Console.ReadKey();
50         }
51     }
52 }

 

posted @ 2016-05-21 23:23  Johar  阅读(3834)  评论(1)  编辑  收藏  举报