字符串数组去重 比较,该怎么解决

字符串数组去重 比较
有一个字符串 string a="123,123,12,124,125,124,"

怎么去掉重复的123和124然后重新得到一个字符串：string b="123,12,124,125,"


帮忙了 用 C#就好。

[解决办法]
以逗号split，然后循环添加到List，天津前判断是否已经存在
[解决办法]

C# code

        string a = "123,123,12,124,125,124,";        string[] result = a.Split(',').Distinct().ToArray();        string b = string.Join(",", result);//结果b等于：123,12,124,125,
[解决办法]
C# code
            string str="123,123,12,124,125,124,";            Regex reg = new Regex(@"((\d+,).*?)\2");            while (str != (str = reg.Replace(str, "$1"))) ;            Console.WriteLine(str);
[解决办法]
探讨


引用:
C# code
while (str != (str = reg.Replace(str, "$1"))) ;
这是个什么循环？

[解决办法]
string a = "123,123,12,124,125,124,";
           string[] str = a.Split(',');

           IEnumerable<string> ling = (from b in str select b).Distinct();
           StringBuilder strbuil = new StringBuilder(100);
           foreach (string s in ling)
           {
               strbuil.Append(s);
           }