using System;
using System.Text.RegularExpressions;
public class Program
{
public static void Main()
string xxx1 = " \t ";
Console.WriteLine($"String xxx1: {xxx1.Length} [{xxx1}]");
string xxx2 = Regex.Replace(xxx1, @"[\s\t]", "");
Console.WriteLine($"String xxx2: {xxx2.Length} [{xxx2}]");
}