The .NET Framework gives us the Format method:
string s = string.Format(\"This {0} very {1}.\", \"is\", \"funny\");
// s is now: \"This is very funny.\"
I reference earlier reply, wrote a sample see following
string sampleinput = "FirstWord.22222";
Match match = Regex.Match(sampleinput, @"(\w+)\.(\d+)$", RegexOptions.IgnoreCase);
if(match.Success){
string totalmatchstring = match.Groups[0]; // FirstWord.22222
string firstpart = match.Groups[1]; // FirstWord`
string secondpart = match.Groups[2]; // 22222
}