Comparing performance difference for Dictionary type & IList Collection type.

c#_dictionary_vs_list.cs

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

namespace Program {

    public static void Man(string[] args) {

        Random rnd = new Random();
        Dictionary<string, long> dic = new Dictionary<string, long>() { };
        var time1 = DateTime.Now;
        for (var i = 0; i < 6000000; i++)
        {
            var number = rnd.Next(100);
            dic.Add("User-" + i, number);
        }
        
        var result = dic.Where(p => p.Value > 95).Where(p=>p.Value > 96).Where(p=>p.Value>97).OrderByDescending(p=>p.Value);
        var resultTime = DateTime.Now - time1;
        Console.WriteLine(result.Count());
        Console.WriteLine(String.Format("Time elapsed: {0}m {1}s {2}ms", resultTime.Minutes, resultTime.Seconds, resultTime.Milliseconds));
        
        Random rnd2 = new Random();
        List<TestUser> dic2 = new List<TestUser>();
        var time2 = DateTime.Now;
        for (var i = 0; i < 6000000; i++)
        {
            var number = rnd2.Next(100);
            dic2.Add(new TestUser { Name = "User-" + i, Age = number });
        }
        
        var result2 = dic2.Where(p => p.Age > 95).Where(p => p.Age > 96).Where(p => p.Age > 97).OrderByDescending(p => p.Age);
        var resultTime2 = DateTime.Now - time2;
        Console.WriteLine(result2.Count());
        Console.WriteLine(String.Format("Time elapsed: {0}m {1}s {2}ms", resultTime2.Minutes, resultTime2.Seconds, resultTime2.Milliseconds));
        
        Console.ReadKey();
        
    }

}