The great thing about regular expression languages is that there are so many to choose from!
Before you ask a question about regular expressions, you should make sure you and your audience agree on which regular expression language you are talking about.
Here is a handy table of which features are supported by which regular expression language.
You can use that table to solve this customer’s problem:
I have a regular expression that works just fine when I test it in 〈insert regular expression testing tool, like RegExr or RegexPlanet〉, but I can’t get it to work in real life.C:\> findstr /r /c:"a(?!.*b)" file.txt (prints no results!) C:\>
My goal is to find all lines that contain an
anot followed anywhere by a