Given a url such as:

http://domain.com/appfile.ext?_uid1=999

I want to store the number 999 in the index.

So I set up spider.config:

PropertyNames uid1
ExtractPath uid1 remove "http://domain.com/appfile.ext"
ExtractPath uid1 remove uid1=

First ExtractPath gives ?_uid1=999
Second ExtractPat gives ?_999

How do I remove ?_

thx