ToList弄ってみた

gistfile1.cs

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

namespace LinqTest2
{
    class Program
    {
        static void Main(string[] args)
        {
            var range1 = Enumerable.Range(1, 10000);
            var range2 = Enumerable.Range(1, 10000);
            var range3 = Enumerable.Range(1, 10000);
            var start = DateTime.Now;
            var list1 = range1.Where(_ => _ % 2 == 0)
                        .Select(_ => (float)_)
                        .ToList();
            Console.WriteLine("{0} ms", (double)(DateTime.Now.Ticks - start.Ticks) / TimeSpan.TicksPerMillisecond);
            start = DateTime.Now;
            var list2 = range2.Where(_ => _ % 2 == 0)
                         .Select(_ => (float)_)
                         .ToListEx();
            Console.WriteLine("{0} ms", (double)(DateTime.Now.Ticks - start.Ticks) / TimeSpan.TicksPerMillisecond);
            start = DateTime.Now;
            var list3 = range3 as ICollection<int>;
            Console.WriteLine("{0} ms", (double)(DateTime.Now.Ticks - start.Ticks) / TimeSpan.TicksPerMillisecond);
            Console.WriteLine("counts: {0}, {1}, {2}", list1.Count, list2.Count, list3 == null ? 0 : list3.Count);
            Console.ReadLine();
        }
    }
    static class ListExtensions
    {
        public static List<T> ToListEx<T>(this IEnumerable<T> source)
        {
            if (source == null)
                throw new ArgumentNullException("source");
            var result = new List<T>();
            foreach (var t in source)
            {
                result.Add(t);
            }
            return result;
        }
    }
}