Difference in PHP and Python regular expressions?

Question

Python

Is there a difference in regular expressions in PHP and Python? What standard is implemented in Python?
In JS, as far as I remember, the possibilities of regular expressions are poorer than in PHP, in particular, there are no back / forward looking (correct if I'm wrong).

Answer 1

https://docs.python.org/3.7/howto/regex.html
php.net/manual/en/regexp.introduction.php = https://en.wikipedia.org/wiki/Perl_Compatible_Regu...