Type of compiled regex object in python

Question

What is the type of the compiled regular expression in python?

In particular, I want to evaluate

isinstance(re.compile(''), ???) 

to be true, for introspection purposes.

One solution I had was, have some global constant REGEX_TYPE = type(re.compile('')), but it doesn't seem very elegant.

EDIT: The reason I want to do this is because I have list of strings and compiled regex objects. I want to "match" a string against list, by

• for each string in the list, try to check for string equality.
• for each regex in the list, try to check whether the string matches the given pattern.

and the code that I came up with was:

for allowed in alloweds:     if isinstance(allowed, basestring) and allowed == input:         ignored = False         break     elif isinstance(allowed, REGEX_TYPE) and allowed.match(input):         ignored = False         break 

Answer 1

Python 3.5 introduced the typing module. Included therein is typing.Pattern, a _TypeAlias.

Starting with Python 3.6, you can simply do:

from typing import Pattern  my_re = re.compile('foo') assert isinstance(my_re, Pattern) 

In 3.5, there used to be a bug requiring you to do this:

assert issubclass(type(my_re), Pattern) 

Which isn’t guaranteed to work according to the documentation and test suite.