Regex to match string containing certain words but not other

Question

I am attempting to write a regex that match words containing "foo" or "bar" but not "baz" anywhere in the string.

/(foo|bar).*(?!baz)/

How do I achieve that?

Use `/^(?!.*baz).*(?:foo|bar)/` – anubhava Nov 13 '19 at 07:37 — anubhava, Nov 13 '19 at 07:37

anubhava · Accepted Answer · 2019-11-13T07:39:23.253

1

You may use this regex:

^(?!.*\bbaz\b).*\b(?:foo|bar)\b

(?!.*\bbaz\b) is negative lookahead condition to fail the match if word baz is found anywhere in your input.

edited Nov 13 '19 at 07:39

answered Nov 13 '19 at 07:38

anubhava

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thanks, how do I have multiple strings in the negative case, like "baz" and "abc"? – Nemo Nov 13 '19 at 07:41
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@Nemo you may use: `^(?!.*\b(?:baz|abc)\b).*\b(?:foo|bar)\b` – anubhava Nov 13 '19 at 07:42
not sure this works: `re.match("^(?!.*\bbaz\b).*\b(?:foo|bar)\b", "foo bar")` return None – Wang Nov 20 '20 at 12:52
@Wang: Use `re.match(r"^(?!.*\bbaz\b).*\b(?:foo|bar)\b", "foo bar")` and read about raw string in Python – anubhava Nov 20 '20 at 13:52

1 Answers1