using System;
using System.Text.RegularExpressions;
public class Example
{
public static void Main()
{
string pattern = @"(?<=watch\?v=|/videos/|/shorts/|/live/|embed\/|youtu.be\/|\/v\/|\/e\/|watch\?v%3D|watch\?feature=player_embedded&v=|%2Fvideos%2F|embed%2F|youtu.be%2F|%2Fv%2F)[^#\&\?\n]*";
string input = @"https://www.youtube.com/live/jfKfPfyJRdk?si=w62kL85ADoUnGlOQ";
Match m = Regex.Match(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