Regex instead of string.replace function

Question

I've seen this CheatSheet for Regex in C#

However, I'm trying to create a regex function which can replace this for me:

while (fname.Contains(".."))
{
    fname = fname.Replace("..", ".");
}
if (fname.StartsWith(".")) { 
    fname=  fname.Remove(0, 1);
}
fname = fname.Replace("&", "_");
fname = fname.Replace("#", "_");
fname = fname.Replace("{", "_");
fname = fname.Replace("}", "_");
fname = fname.Replace("%", "_");
fname = fname.Replace("~", "_");
fname = fname.Replace("?", "_");

I simply don't get how to write the regex which will fix this issue for me. Can anyone give me a hand?

Answer 1

string dotsPattern = @"\.\.+"; //2 or more dots.
fname=Regex.Replace(fname, dotsPattern ,".");
String firstSymbolDot = @"^\.";
fname = Regex.Replace(fname, firstSymbolDot, String.Empty);
string symbolPattern = "[&#{}%~?]"; //any of given symbol;
string result = Regex.Replace(fname, symbolPattern, "_");