Pattern matching in C# with Regex

A regular expression is a pattern that could be matched against an input text. A pattern consists of one or more character literals, operators, or constructs.

Let us see an example to display the words starting with the letter ‘M’ using Regex.

Example

using System;
using System.Text.RegularExpressions;

namespace Demo {
   class Program {
      private static void showMatch(string text, string expr) {
         Console.WriteLine("The Expression: " + expr);
         MatchCollection mc = Regex.Matches(text, expr);
         foreach (Match m in mc) {
            Console.WriteLine(m);
         }
      }

      static void Main(string[] args) {
         string str = "Mandatory requirements for a Cricket Match Event!";

         Console.WriteLine("Matching words that start with 'M': ");
         showMatch(str, @"\bM\S*");
         Console.ReadKey();
      }
   }
}

Output

Matching words that start with 'M':
The Expression: \bM\S*
Mandatory
Match

Above, I have the string.

string str = "Mandatory requirements for a Cricket Match Event!";

To get all the words that begin with ‘M’, I have used the following pattern −

@"\bM\S*