OR combine two lookaheads

Question

I am successfully chaining two negative regex (C#/.NET) lookaheads to exclude <html> tags that contain ' amp' or ' ⚡':

regex101

<\s*?html((?!.*?\samp[\s>])(?!.*?\s⚡[\s>]).*?)>

But I was searching for a possibility to OR combine the two searches, something like [amp|⚡]:

<\s*?html((?!.*?\s[⚡|amp][\s>]).*?)>

Is that possible, and if so, what would be the correct syntax?

EDIT: I had an error in the initial question, because it didn't show quite what I wanted to capture: everything after html up to >, if it doesn't include amp or ⚡. Now the statements are right and also the regEx101. And a good solution has also been commented, that is to use () instead of []. So my current working solution is:

<\s*?html(
  (?!
    .*?
    \s(⚡|amp)[\s>]
  )
.*?)>

sometimes the solution is so close and you don't see it. thanks @lancylot2004 — jamacoe, Aug 20 '22 at 12:45
Note that `.*` will not work if the tag is split on multiple lines. — Poul Bak, Aug 20 '22 at 12:47
@DanielA.White I've heard that before: [https://stackoverflow.com/a/1732454/4335480](https://stackoverflow.com/a/1732454/4335480). But it works for me in this situation. — jamacoe, Aug 20 '22 at 14:26

The fourth bird · Answer 1 · 2022-08-20T13:58:36.613

The correct syntax is using a group instead of a character class, but the pattern also has a few unnecessary parts.

You can remove .*? at the end as it will not match anything because it is optional, and adds nothing to the assertion.
You can remove the parenthesis here (.*)? including the question mark as the .* is already optional
You can remove the whole outer capturing group because the pattern inside it does not match anything.

If there are no further angle brackets after the opening <html you can write it as:

<html(?![^<>]* (?:amp|⚡)[ >])

Explanation

<html Match literally
(?! Negative lookahead
- [^<>]* Optionally match any char except < and >
- (?:amp|⚡)[ >] Match a space, either amp or ⚡ followed by either a space or >
) Close the lookahead

Regex demo

OR combine two lookaheads

1 Answers1