Use negative lookaround: (?!pattern)
Positive lookarounds can be used to assert that a pattern matches. Negative lookarounds is the opposite: it’s used to assert that a pattern DOES NOT match. Some flavor supports assertions; some puts limitations on lookbehind, etc.
Links to regular-expressions.info
- Lookahead and Lookbehind Zero-Width Assertions
- Flavor comparison
See also
- How do I convert CamelCase into human-readable names in Java?
- Regex for all strings not containing a string?
- A regex to match a substring that isn’t followed by a certain other substring.
More examples
These are attempts to come up with regex solutions to toy problems as exercises; they should be educational if you’re trying to learn the various ways you can use lookarounds (nesting them, using them to capture, etc):
- codingBat plusOut using regex
- codingBat repeatEnd using regex
- codingbat wordEnds using regex