using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        string[] arrs = { "L0021_21.jpg", "L0029_29.jpg", "L0033_33.jpg",

                                "R0025_25.jpg", "R0029_29.jpg", "R0030_30.jpg",

                                "K0028_28.jpg", "K0029_29.jpg", "K0030_30.jpg"};

            Console.WriteLine("原单数组：" + string.Join(" ", arrs));

            Console.WriteLine("\t\n单数组转换后的结果：\t\n");

            var result = arrs.GroupBy(p => p, new CustomEqualityComparer()).ToList();

            foreach(var item in result)

            {

                string str = string.Join(" ", item);

                Console.WriteLine("数组：" + str);

            }

​

    }

}

​

public class CustomEqualityComparer:IEqualityComparer<string>

{

    #region IEqualityComparer<string> 成员

        public bool Equals(string x, string y)

    {

        return Equals(x.ToArray().FirstOrDefault(), y.ToArray().FirstOrDefault());

    }

    public int GetHashCode(string obj)

    {

        return obj.ToArray().FirstOrDefault().GetHashCode();

    }

    #endregion

}