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CSharp · Console

/Program.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Linq.Expressions;

public class Program
{
	public static void Main()
	{
		var k1 = new List<int>(){1,2,3,4,5};
		var k2 = new List<int>(){1,2,3,4,5};
		
		var o1 = new A(){k=k1, objectName="o1"};
		var o2 = new A(){k=k2, objectName="o2"};
		
		var l = new List<A>();
		
		l.Add(o1);
		l.Add(o2);
		
		var b = l.GroupBy(a => a.k, new ListComparer<int>())
				 .Select(g => new 
					{
						Key = String.Join(",", g.Key.Select(i => i)), 
						n = String.Join(",",g.Select(i => i.objectName))
					});
		
		
		foreach(var item in b)
		{
			Console.WriteLine(string.Format("{0} : {1}", item.Key, item.n));
		}
	}
	
	public class A
	{
		public List<int> k;
		public string objectName;
	}
	
	
	public class ListComparer<T> : IEqualityComparer<List<T>>
	{
		public bool Equals(List<T> left, List<T> right)
		{
			return left.OrderBy(i => i).SequenceEqual(right.OrderBy(i => i));
		}
		
		public int GetHashCode(List<T> list)
		{
			return list.Count;
		}
	}
	
}