Question

I’ve created the following regex pattern in an attempt to match a string 6 characters in length ending in either ‘PRI’ or ‘SEC’, unless the string = ‘SIGSEC’. For example, I want to match ABCPRI, XYZPRI, ABCSEC and XYZSEC, but not SIGSEC.

(\w{3}PRI$|[^SIG].*SEC$) 

It is very close and sort of works (if I pass in ‘SINSEC’, it returns a partial match on ‘NSEC’), but I don’t have a good feeling about it in its current form. Also, I may have a need to add more exclusions besides ‘SIG’ later and realize that this probably won’t scale too well. Any ideas?

BTW, I’m using System.Text.RegularExpressions.Regex.Match() in C#

Thanks, Rich

Answer 1

Assuming your regex engine supports negative lookaheads, try this:

((?!SIGSEC)\w{3}(?:SEC|PRI)) 

Edit: A commenter pointed out that .NET does support negative lookaheads, so this should work fine (thanks, Charlie).