Regex - optional capture group after wildcard - regex

Question

Say I have the following list:
No 1 And Your Bird Can Sing (4)
No 2 Baby, You're a Rich Man (5)
No 3 Blue Jay Way S
No 4 Everybody's Got Something to Hide Except Me and My Monkey (1)
And I want to extract the number, the title and the number of weeks in the parenthesis if it exists.
Works, but the last group is not optional (regstorm):
No (?<no>\d{1,3}) (?<title>.*?) \((?<weeks>\d)\)
Last group optional, only matches number (regstorm):
No (?<no>\d{1,3}) (?<title>.*?)( \((?<weeks>\d)\))?
Combining one pattern with week capture with a pattern without week capture works, but there gotta be a better way:
(No (?<no>\d{1,3}) (?<title>.*) \((?<weeks>\d)\))|(No (?<no>\d{1,3}) (?<title>.*))
I use C# and javascript but I guess this is a general regex question.

Answer 1

Your regex is almost there!
First and most importantly, you should add a $ at the end. This makes (?<title>.*?) match all the way towards the end of the string. Currently, (?<title>.*?) matches an empty string and then stops, because it realises that it has reached a point where the rest of the regex matches. Why does the rest of the regex match? Because the optional group can match any empty string. By putting the $, you are making the rest of the regex "harder" to match.
Secondly, you forgot to match an open parenthesis \(.
This is how your regex should look like:
No (?<no>\d{1,3}) (?<title>.*?)( \((?<weeks>\d)\))?$
Demo

Answer 2

You may use this regex with an optional last part:
^No (?<no>\d{1,3}) (?<title>.*?\S)(?: \((?<weeks>\d)\))?$
RegEx Demo

Answer 3

Another option could be for the title to match either not ( or when it does encounter a ( it should not be followed by a digit and a closing parenthesis.
^No (?<no>\d{1,3}) (?<title>(?:[^(\r\n]+|\((?!\d\)))+)(?:\((?<weeks>\d)\))?
In parts
^No
(?\d{1,3}) Group no and space
(?<title>
(?: Non capturing group
[^(\r\n]+ Match any char except ( or newline
| Or
\((?!\d\)) Match ( if not directly followed by a digit and )
)+ Close group and repeat 1+ times
) Close group title
(?: Non capturing group
\((?<weeks>\d)\) Group weeks between parenthesis
)? Close group and make it optional
Regex demo
If you don't want to trim the last space of the title you could exclude it from matching before the weeks.
Regex demo