Need a regex to exclude certain strings

Question

I\'m trying to get a regex that will match:

somefile_1.txt
somefile_2.txt
somefile_{anything}.txt

but not match:

somefile_1         


        

Answer 1

Sometimes it's just easier to use two regular expressions. First look for everything you want, then ignore everything you don't. I do this all the time on the command line where I pipe a regex that gets a superset into another regex that ignores stuff I don't want.

If the goal is to get the job done rather than find the perfect regex, consider that approach. It's often much easier to write and understand than a regex that makes use of exotic features.