Sorry, but your question is not clear...
Seems you want to find a substring within a title... Regex is not for such of requirements.
If you want to get a text within a "
group-title=
", try this:
.group-title=\"(.*?)\"
Example:
regex101: build, test, and debug regex[
^]
For further details:
Regular Expression Tutorial - Learn How to Use Regular Expressions[
^]
[EDIT]
string mystring = @"#EXTINF:-1, tvg-name='THE NAME' tvg-logo='THE LOGO' group-title='THE TITLE',THE ITEM
https://www.SampleSite.com";
string pattern = ".group-title=\'(.*?)\'";
Regex r = new Regex(pattern);
MatchCollection mc = r.Matches(mystring);
foreach(Match m in mc)
Console.WriteLine($"{m.Index} => {m.Value}");
In case you want to use ["] instead of ['] in a string, use double ["], for ex.:
string mystring = @"#EXTINF:-1, tvg-name=""THE NAME"" tvg-logo=""THE LOGO"" group-title=""THE TITLE"",THE ITEM
https://www.SampleSite.com";
is equivalent to previous statement.