csharp_regex

gistfile1.txt

using System;
using System.Text.RegularExpressions;

class Program
{
    static void Main()
    {
        // https://www.mikesdotnetting.com/article/46/c-regular-expressions-cheat-sheet

        string emailAddress = "[email protected]";
        string emailPattern = @"^\w+@[a-zA-Z_]+\.[a-zA-Z]{2,3}$";
        // string emailPattern = @"^\w+@\w+\.\w+$"; // This also works.

        if (Regex.IsMatch(emailAddress, emailPattern))
        {
            Console.WriteLine("Valid email address.");
        }
        else
        {
            Console.WriteLine("Invalid email address.");
        }

        string phoneNumber = "(123) 456-7890";
        string phonePattern = @"\((\d{3})\)";
        
        Match match1 = Regex.Match(phoneNumber, phonePattern);
        
        if (match1.Success)
        {
            string areaCode = match1.Groups[1].Value;
            Console.WriteLine("Area code: " + areaCode);
        }
        else
        {
            Console.WriteLine("Area code not found.");
        }

        string text = "My phone number is (123) 456-7890.";
        string phonePattern2 = @"\((\d{3})\) (\d{3})-(\d{4})"; // \( (\d{3}) \) 
        
        Match match = Regex.Match(text, phonePattern2);
        
        if (match.Success)
        {
            string areaCode = match.Groups[1].Value;
            string firstPart = match.Groups[2].Value;
            string secondPart = match.Groups[3].Value;
            
            Console.WriteLine($"Area Code: {areaCode}");
            Console.WriteLine($"First Part: {firstPart}");
            Console.WriteLine($"Second Part: {secondPart}");
        }
        else
        {
            Console.WriteLine("Phone number not found.");
        }

        // Multi-part extraction
        /*
            Month	    Month Code
            January	    F
            February	G
            March	    H
            April	    J
            May	        K
            June	    M
            July	    N
            August	    Q
            September	U
            October	    V
            November	X
            December	Z
        Examples: https://www.cmegroup.com/markets/cryptocurrencies/bitcoin/bitcoin.quotes.html#venue=globex
        */
        string futureCode = "BTCH24";
        string futureCodePattern = @"^(?<token>[A-Z]{3})(?<futureMonthCode>[A-Z])(?<year>\d+)+$";
        Match futureCodeMatch = Regex.Match(futureCode, futureCodePattern);
        if (futureCodeMatch.Success)
        {
            string token = futureCodeMatch.Groups["token"].Value;
            string monthCode = futureCodeMatch.Groups["futureMonthCode"].Value;
            int year = Convert.ToInt32(futureCodeMatch.Groups["year"].Value);
            Console.WriteLine($"futureCode: {futureCode}, token: {token}, monthCode: {monthCode}, year: {year}");
        }

    }
}