Regex with exclusion chars and another regex

Question

How to write regex which find word (without whitespace) that doesn't contain some chars (like * or #) and sentence also (like level10 or level2 - it should be also regex - level[0-9]+). It will be simple for chars excluded ([^\\s^#^*]+) but how to exclude this 'level' example too ?

I want to exclude chars AND level with number.

Examples:
- weesdlevel3fv - shouldn't match because of 'level3'
- we3rlevelw4erw - should match - there is level without number
- dfs3leveldfvws#3vd - shouldn't match - level is good, but '#' char appeared
- level4#level levelw4_level - threat as two words because of whitespaces - only second one should match - no levels with number and no restricted chars like '#' or '*'

Please give more examples of valid and invalid input, and show what you tried. — Lucas Trzesniewski, Aug 05 '14 at 18:00

score 3 · Answer 1 · edited Jan 18 '21 at 12:34

3

See this regex:

/(?<=\s)(?!\S*[#*])(?!\S*level[0-9])\S+/

Regex explanation:

(?<=\s) Asserts position after a whitespace sequence.
(?!\S*[#*]) Asserts that "#" or "*" is absent in the sequence.
(?!\S*level[0-9]) Asserts that level[0-9] is not matched in the sequence.
\S+Now that our conditionals pass, this sequence is valid. Go ahead and use \S+ or \S++ to match the entire sequence.

To use lookaheads more exclusively, you can add another (?!\S*<false_to_assert>) group.

View a regex demo!

For this specific case you can use a double negation trick:

/(?<=\s)(?!\S*level[0-9])[^\s#*]+(?=\s)/

Another regex demo.

Read more:

Regex for existence of some words whose order doesn't matter

edited Jan 18 '21 at 12:34

Community

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answered Aug 06 '14 at 00:16

Unihedron

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Thanks for answer and explanation. I tried it at 'weesdlevel3fv we3rlevel4erw dfsdfv#levels3vd fvlevels3vd' - should match last word but match last 3 – Archaon Aug 06 '14 at 06:44
@Archaon In [tag:regex], a `word` is defined as a collection of `\w` (word characters `[A-Za-z0-9_]`) surrounded by `\W` (non-word characters). I _assume_ you meant that you are looking to match non-whitespace sequences (`\S`) between whitespaces (`\s`) then? – Unihedron Aug 06 '14 at 06:47
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+1 for efficient use of [classic password validation technique](http://www.rexegg.com/regex-lookarounds.html). – zx81 Aug 06 '14 at 10:16

score -1 · Answer 2 · edited Aug 05 '14 at 18:10

-1

you can simply OR the searches with the pipe character [^\s#*]+|level[0-9]+

edited Aug 05 '14 at 18:10

Brad

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answered Aug 05 '14 at 18:02

Tag Groff

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Regex with exclusion chars and another regex

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