using System;
using System.Text.RegularExpressions;
public class Example
{
public static void Main()
{
string pattern = @"^20([0-2][0-9])(\.(0[1-9]|1[012])(\.(0[1-9]|1[0-9]|2[0-9]|3[01]))?)?_([a-z]{1,24}((\-)?[a-z]{1,16})?)((\.[a-z]{1})|(\.[a-z]{1,16}\.[a-z]{1}))?_(([a-z]{1,24}((\-)?[a-z]{1,16})?)(\.[a-z]{1,16}(\.[a-z]{1,16}(\.[a-z]{1,16})?)?)?)?_(m|w)$";
string input = @"2012.11.09_mary.a_san.luis.obispo_w
";
RegexOptions options = RegexOptions.Multiline;
Match m = Regex.Match(input, pattern, options);
Console.WriteLine("'{0}' found at index {1}", m.Value, m.Index);
}
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for C#, please visit: https://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex(v=vs.110).aspx