Hi David,
Sure and I am glad it’s helpful!
Best,
Paul

Hi Paul,
Many thanks for your response. It’s very useful. Much appreciate.
Everything is far more clear now and I am more than sure that I will use that in the future.
Also thanks for the testing tools.
Regards,
David

Hi David,
Great to hear from you and I am glad this post is useful!

This is a tricky RegEx and I had been playing around for a while – used some others first.

The ^ and ? match is used to remove a part of the URL that contains ?, but please note that ^? won’t work without using brackets, which means “not”. Otherwise it’s an invalid RegEx.

Let’s deconstruct it:
^([^?]+)

– First anchor ^ Matches the beginning of the string. If you don’t use it, it will also match the query parameter (not including ? itself).
– () Groups multiple tokens together and creates a capture group for extracting a substring or using a backreference.
– [^?]+ Creates a negated set that includes ? -> to remove ? and everything behind from the URL. Without the +, it would match only an opening / (slash) I think.

I have validated this RegEx in several accounts, all positive.

Sometimes a RegEx can get really complicated, hope this helps a bit!

These tools can be really powerful when you are testing:
https://regex101.com/
https://regexr.com/

Best,
Paul