C# Linq排序

今天在家看了一下linq，實踐了一下書中代碼，發現排序和查重的先后順序太重要了。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace LinqLearning
{
    class Program
    {
        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;
        }

        static void Main(string[] args)
        {
            int[] numbers = GenerateLotsOfNumbers(12345678);

            var queryResults = from n in numbers
                               where n < 1000
                               orderby n descending
                               select n;
            Console.WriteLine("查詢語法排序結果：");
            DateTime start = DateTime.Now;
            foreach (var item in queryResults)
                Console.WriteLine(item);
            Console.WriteLine("消耗時間：{0}",DateTime.Now-start);

            var queryResult = numbers.OrderByDescending(n => n).Where(n => n < 1000);
            Console.WriteLine("方法排序結果（排序字段在前）：");
            start = DateTime.Now;
            foreach (var item in queryResult)
                Console.WriteLine(item);
            Console.WriteLine("消耗時間：{0}", DateTime.Now - start);

            var query = numbers.Where(n => n < 1000).OrderByDescending(n => n);
            Console.WriteLine("方法排序結果（排序字段在后）：");
            start = DateTime.Now;
            foreach (var item in query)
                Console.WriteLine(item);
            Console.WriteLine("消耗時間：{0}", DateTime.Now - start);

            Console.ReadKey();
        }
    }
}