I have books in several different formats. This regex seems to cover most of them. Examples:
JR Ward - [Black Dagger Brotherhood 03] - Lover Awakened (epub).epub
JR Ward - Black Dagger Brotherhood 03 - Lover Awakened.epub
JR Ward - Lover Awakened.epub
I got it from an example on this forum. It is not my own but it seems to work better than the ones I was originally using. I had to switch back and forth between them to make them work and they didn't work for all my files.
(?P<author>[^_]+) - (?P<title>.+)
(?P<author>[^_]+) - (?P<series>[^-]+) (?P<series_index>[^-]+) - (?P<title>.+)
Thanks so much for your help