Title to Metadata

[Trialjudge]

I would like to use a file name of "Title - Author" for my Calibre catalog. But sometimes I want to use a file name of "Series ~ Title - Author" So I set my regular expression to:
(?P<series>.+) ~ (?P<title>.+) - (?P<author>[^_]+)

For example, "Bond ~ Diamonds Are Forever - Ian Fleming" works beautifully.

But if there is NO series, such as:

"Basic English - Henrietta Hornswaggle", Calibre doesn't read it.

I'm pretty sure the problem is I've written the wrong regular expression
(?P<series>.+) ~ (?P<title>.+) - (?P<author>[^_]+)
But I can't figure out how to do it correctly.

Any help would be greatly GREATLY appreciated.

Thanks!!!

TrialJudge AT aol.com