Negative look-ahead assertion (?!...)
Q
What is a negative look-ahead assertion? How to use it?
How to write a regular expression to find words without 'oo' in text like: how, to, look, google, school?
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A
A negative look-ahead assertion is a zero-width assertion that allows you to not match a subpattern beyond the current position (look-ahead) without moving the matching position. Positive look-ahead assertion is expressed as (?!pattern). For example:
\w+(?!-) - matches a word not followed by a '-'
The regular expression to match find words without 'oo' is:
+(?!\w*oo)(\w+)
+ - skip space characters
(?!\w*oo) - any word without '00' ahead?
(\w+) - capture the word
2013-01-26, 2458👍, 0💬