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  1. using System;
  2. using System.Collections.Generic;
  3. using System.Diagnostics;
  4. using System.Linq;
  5.  
  6. public static class ConsoleSandbox
  7. {
  8.     public class PropA
  9.     {
  10.         public int a { get; set; }
  11.         public int b { get; set; }
  12.     }
  13.     public class PropX
  14.     {
  15.         public int a { get; set; }
  16.         public int b { get; set; }
  17.     }
  18.     private static void Main()
  19.     {
  20.         List<PropA> first = new List<PropA>();
  21.         List<PropX> second = new List<PropX>();
  22.  
  23.         int numItems = 5000;
  24.         Random generator = new Random(0);
  25.         for (int i = 0; i < numItems; i++)
  26.         {
  27.             first.Add(new PropA() { b = i });
  28.             second.Add(new PropX() { b = i });
  29.         }
  30.  
  31.         first.Shuffle(generator);
  32.         second.Shuffle(generator);
  33.  
  34.         Stopwatch watch = new Stopwatch();
  35.         watch.Start();
  36.  
  37.         var query = from firstItem in first
  38.                     join secondItem in second
  39.                     on firstItem.b equals secondItem.b
  40.                     select firstItem;
  41.         Console.WriteLine(query.Count());
  42.         var firstDuration = watch.Elapsed;
  43.         Console.WriteLine(watch.Elapsed);
  44.         watch.Reset();
  45.         watch.Start();
  46.  
  47.         var query2 = first.Where(a => second.Any(x => x.b == a.b));
  48.  
  49.         Console.WriteLine(query2.Count());
  50.         Console.WriteLine(watch.Elapsed);
  51.  
  52.         Console.WriteLine();
  53.         Console.WriteLine(firstDuration - watch.Elapsed);
  54.  
  55.         Console.WriteLine();
  56.         Console.WriteLine("press any key to exit . . .");
  57.         Console.ReadKey();
  58.     }
  59.  
  60.     public static void Shuffle<T>(this IList<T> list, Random generator)
  61.     {
  62.         for (int i = list.Count - 1; i > 0; i--)
  63.         {
  64.             int next = generator.Next(i + 1);
  65.             T temp = list[i];
  66.             list[i] = list[next];
  67.             list[next] = temp;
  68.         }
  69.     }
  70. }
Success #stdin #stdout 2.45s 35816KB
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Standard input is empty
stdout
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5000
00:00:00.0535029
5000
00:00:02.3779080

-00:00:02.3248531

press any key to exit . . .
https://ideone.com/xW1CnL
language:
C# (gmcs 5.20.1)
created:
11 years ago
visibility:
public

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