Question

I would like to find the string position of the (test) string from the string below (the one that neither start with for or or):

 •  <test>* (for test) (or test) (test)

Is it possible to find the specific string using negative look behind assertion? I was using this regex but i am missing something:

m_comments = re.search('(?<!\(for)|(?<!\(or)', line)

also can we combine an or statement in a look behind assertion?

Note: test can be any possible string:

<an other eg> (for another test) (or with this) (anything)

Answer 1

Try this

\((?!for|or).*?\)

see it here on Regexr

With the \(.*?\) I am matching everything from an opening bracket to the first closing bracket.

Then I use a negative lookahead (?!for|or) to ensure that there is no “for” and no “or” directly after the opening bracket.

In a lookbehind assertion in Python it is not possible to use alternations. They have to be of fixed length.