using System;
using System.Text.RegularExpressions;
public class Example
{
public static void Main()
{
string pattern = @"(?:https?:\/\/)(?:www\.)?(?:youtube|youtu)\.(?:be|com)\/[^\s]+";
string input = @"hi how are you check it https://www.youtube.com/watch?v=r_p8ZXIRFJI youtube link can be of this type https://youtu.be/_3tVL-ZAc4k";
foreach (Match m in Regex.Matches(input, pattern))
{
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