C# Regular Expression Regex class

using System;

using System.Text.RegularExpressions;

namespace ConsoleRegex

{

    class Program

    {

        static void Main(string[] args)

        {

//pattern is a string which alphanumeric characters/symbols have meaning beyond the normal meaning. So, also called metacharacter. meta = beyond. For example, [ ] - etc.

            string strPattern = "[0-9]"; // search a digit from the range of digits between 0 and 9

            // Regex is an immutable class

            // regex is a object which is constructed by passing pattern

            // Regex class constructor is parameterized. Overloaded constructors are also to provide case                //insensitive match. RegexOptions.IgnoreCase or RegexOptions.Singleline, 

            //RegexOptions.Multiline or RegexOptions.IgnorePatternWhitespace:

            Regex regex = new Regex(strPattern);

            Console.WriteLine(regex.ToString()); // get the pattern or regular expression

            string strInput = "Number 13 is lucky or not?";

            //Match method of regex returns an object of Match class

            Match match = regex.Match(strInput);

            Console.WriteLine(match.Success);

            Console.WriteLine(match.Value);

            Console.WriteLine(match.Index);//1 is at 7th position, 0-based index

           

            Console.WriteLine(regex.IsMatch(strInput));

            //Matches() method returns a collection of Match type objects called MatchCollection class

            foreach (Match m in regex.Matches(strInput))

            {

                Console.WriteLine(m.Value);

            }

            foreach (var item in regex.Split(strInput))

            {

                Console.WriteLine("... "+item);

            }

            Console.ReadKey();

        }

    }

}

OUTPUT

[0-9]

True

1

7

True

1

3

... Number

...

...  is lucky or not?

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