Question

my first time here, title is bad i know 🙂

Well, this is what i’m trying to do

Input possibility 1: SOMETHING BLAH always same words here (here comes date/time text, called group 1) [group 2 text]: (group 3 text) END

Input 2: SOMETHING BLAH [group 2 text] always same words here (here comes date/time text, called group 1): (group 3 text) END

group2 can appear before or after

Now, using python and module re, is it possible to match either of these inputs using only 1 regex?

Example (Obviously, something like this is not possible as it contains same name groups):

"SOMETHING BLAH (always same words here \((?P<group1>.{1,40})\) \[(?P<group2>.*?)\]: \((?P<group3>.*?)\)|\[(?P<group2>.*?)\] always same words here \((?P<group1>.{1,40})\): (group 3 text) ) END", re.DOTALL

It’s just an exmp for what im trying to do

Answer 1

Sure, you use optional groups:

>>> patt = re.compile("foo (?P<name>[0-9]+)?")
>>> patt.search("blah foo 999 bar").groupdict()
{'name': '999'}
>>> patt.search("blah foo bar").groupdict()
{'name': None}

Your example, somewhat simplified for length:

prefix (?P<optional1>\[.*?\])? same-words \((?P<date>.*?)\)(?P<optional2> \[.*?\])?: \((?P<g3>.*?)\) END

Then once you have a match, you can do:

d = patt.search(str).groupdict()
g2 = d["optional1"] if d["optional1"] is not None else d["optional2"]