相同字符串合并问题

Question

“122222####3333###sda”
我想让#只显示一次，显示效果如下
“122222#3333#sda”

Answer 1

string s = "122222####3333###sda";
string r = Regex.Replace(s, @"#+", "#");
Response.Write(r);

Answer 2

string[] str=“122222####3333###sda”.split("#");
private string[] getOnly(string[] strArry)
        {
            List<string> list = new List<string>();
            foreach (string str in strArry)
            {
                if (!list.Contains(str))
                {
                    list.Add(str);
                }
            }            string strA = "";
            foreach (string s in list)
            {
                strA += s + ",";
            }
            string[] arry = strA.Split(',');
            return arry;
        }string[] s=getOnly(str);
for(int i=0;i<s.length;i++)
{
   if(s[i]!="")
   {
      string aa+=s[i];
   }
}

Answer 3

string result = Regex.Replace(yourStr,@"(\D)\1+","$1");

Answer 4

追求效率吗？
如果追求效率的话用这个吧，我为了效率而写的。比正则方法快1到3倍吧
用时是 Regex.Replace(s, @"#+", "#"); 的一半
是 Regex.Replace(yourStr,@"(\D)\1+","$1");的四分之一
string TrimChar(string str,char c) 
        {
            StringBuilder builder = new StringBuilder();
            bool lastOneflag = false;
            for (int i = 0; i < str.Length;i++ )
            {
                if (str[i] != c)
                {
                    builder.Append(str[i]);
                    lastOneflag = false;
                }
                else 
                {
                    if (lastOneflag == true)
                    {
                        continue;
                    }
                    else 
                    {
                        builder.Append(str[i]);
                        lastOneflag = true;
                    }
                }
            }
            return builder.ToString();
        }