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jonelf/gist:3916414

Created October 19, 2012 05:42
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  1. jonelf created this gist Oct 19, 2012.
    91 changes: 91 additions & 0 deletions gistfile1.cs
    View file
    Original file line number Diff line number Diff line change
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    using System;
    using System.Diagnostics;
    using System.Collections.Generic;
    using System.Linq;

    namespace test
    {
    class Person
    {
    public int Number { get; set; }
    public string Name { get; set; }
    }

    class PersonComparer : IEqualityComparer<Person>
    {
    public bool Equals(Person p1, Person p2)
    {
    return p1.Number == p2.Number;
    }

    public int GetHashCode(Person p)
    {
    return p.Number;
    }
    }

    class MainClass
    {
    public static void Main(string[] args)
    {
    var nameParts = new[] { "fe", "se", "ra", "ko", "il", "as", "os", "de", "ik" };
    var rnd = new Random();

    var list1 = Enumerable.Range( 0, 1000).Select(n => new Person() { Number = n, Name = RandomName(rnd, nameParts) }).ToList();
    var list2 = Enumerable.Range(500, 1000).Select(n => new Person() { Number = n, Name = RandomName(rnd, nameParts) }).ToList();

    var watch = new Stopwatch();

    for (int _ = 0; _ < 5; _++)
    {
    Console.Write("Lists and LINQ merge: ");
    watch.Restart();
    for (int i = 0; i < 100; i++)
    {
    var merged = new List<Person>(list1);
    merged.AddRange(list2.Where(p2 => list1.All(p1 => p1.Number != p2.Number)));
    }
    Console.WriteLine(watch.ElapsedMilliseconds + "ms");

    Console.Write("Dictionary merge: ");
    watch.Restart();
    for (int i = 0; i < 100; i++)
    {
    var dict = list2.ToDictionary(p => p.Number);
    foreach (var person in list1)
    {
    dict[person.Number] = person;
    }
    var merged = dict.Values.ToList();
    }
    Console.WriteLine(watch.ElapsedMilliseconds + "ms");

    Console.Write("LINQ Union and IEqualityComparer: ");
    watch.Restart();
    for (int i = 0; i < 100; i++)
    {
    var merged = list1.Union(list2, new PersonComparer()).ToList();
    }
    Console.WriteLine(watch.ElapsedMilliseconds + "ms");

    Console.Write("HashSet and IEqualityComparer: ");
    watch.Restart();
    for (int i = 0; i < 100; i++)
    {
    var hs = new HashSet<Person>(list1, new PersonComparer());
    hs.UnionWith(list2);
    var merged = hs.ToList();
    }
    Console.WriteLine(watch.ElapsedMilliseconds + "ms\n");
    }

    Console.ReadKey();
    }

    public static string RandomName(Random rnd, string[] nameParts)
    {
    return String.Join("", Enumerable.Range(0, 4).Select(_ => nameParts[rnd.Next(nameParts.Length)]).ToArray());
    }

    }
    }