Regular expressions·a line that does not contain a given word

a line that does not contain a given word

Matches a line that does not contain a given word. It is anchored at both ends, so the whole string has to match. There are no capture groups.

Pattern
/^(?!.*\btest\b).*$/
Match scope
the whole string
Capture groups
0
What it catches in the first example
production code

Try it yourself

Type any text and the parts this expression catches are highlighted. It runs in your browser and is never sent anywhere.

production code

1 match

Examples that match

  • production code
  • testing

Examples that do not match

  • this is a test
  • test

Other expressions in this group

How to read this

  • With ^ and $ around it, the whole string must match; without them the match can sit anywhere. Always anchor an expression you use for validation.
  • Round brackets ( ) capture what they wrap. When you only need grouping, write (?: ) so the numbering of later groups does not shift.
  • Every expression here is checked against its examples. Even so, "looks like an email" and "is a real inbox" remain different questions.
  • Nested open-ended repeats such as (a+)+ can blow up on certain inputs. Look for that shape before pasting someone else’s expression into your code.

Frequently asked questions

Q. What is the regex for a line that does not contain a given word?

^(?!.*\btest\b).*$.

Q. Which strings match?

Text like production code matches; text like this is a test does not.

Q. Does the whole string have to match?

Yes. It is wrapped in ^ and $, so nothing but a full match passes.

Q. How do I use what it caught?

There are no capture groups, so only the whole match (match[0]) comes back. Wrap the part you need in brackets to capture it.