问使用Linq查找包含一组对象的实例

EN

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

namespace Project
{
    public enum Marble { Red, Green, Blue}

    public class Bag {
        public string Name;
        public List<Marble> contents;
    }

    class Program
    {
        static void Main()
        {
            var marbles = new[] { Marble.Red, Marble.Green };
            var bags = new[] 
            {
                new Bag {Name = "Foo", contents = new List<Marble> {Marble.Blue}},
                new Bag {Name = "Bar", contents = new List<Marble> {Marble.Green, Marble.Red}},
                new Bag {Name = "Baz", contents = new List<Marble> {Marble.Red, Marble.Green, Marble.Blue}},
                new Bag {Name = "Foo", contents = new List<Marble> {Marble.Blue}},
                new Bag {Name = "Bar", contents = new List<Marble> {Marble.Green, Marble.Red}},
                new Bag {Name = "Fiz", contents = new List<Marble> {Marble.Red, Marble.Green}},
                new Bag {Name = "REDS", contents = new List<Marble> {Marble.Red, Marble.Red}},
                new Bag {Name = "Biz", contents = new List<Marble> { Marble.Red } }, 
                new Bag {Name = "Griz", contents = new List<Marble> {Marble.Green, Marble.Green, Marble.Blue}},
                new Bag {Name = "Baz", contents = new List<Marble> {Marble.Red, Marble.Green, Marble.Blue}}
            };

            // the method call version with set substraction operator
            var query_v2 = bags.Where(bag => bag.contents.Except(marbles).Count() == 0 &&
                                             marbles.Except(bag.contents).Count() == 0                                            
                                     );

            // print out the results 
            Console.WriteLine("query_v2...");
            foreach (var bag in query_v2)
            {
                Console.WriteLine(bag.Name);
            }
            Console.WriteLine();

            // Follwowing is a LINQ Expression version
            var linqversion = from bag in bags
                              let diff1 = bag.contents.Except(marbles).Count()
                              let diff2 = marbles.Except(bag.contents).Count()
                              where diff1 == 0 && diff2 == 0 // perfect match ?
                              select bag;

            Console.WriteLine("Linq expression version output...");
            foreach (var bag in linqversion)
            {
                Console.WriteLine(bag.Name);
            }
            Console.ReadLine();
        }
    }
}