Python - Regex on content between repeating strings

Question

I have a string which looks like this :

 Q 1. What is your age?

Ans. 15.

Q 2. What is your name?

Ans. My name is Bond. 


My full name is James Bond

Q 3. What is your favorite subject?

and so on... The answers can have multiple paragraphs. The text generally looks like and so on.. I am trying to write a regex which gives me these pairs. I want to separate out the question answer pairs. I have a regex which outputs the questions but am unable to figure out how to get the pairs? Please guide. The regex for questions is :

p = re.findall("""Q [0-9]+[a-zA-Z]*\.(.*?)Ans\.""", checkText, re.S)

Do you need to do this with a regex? wouldn't it be easier to use stringIO and iterate over the lines? — jprockbelly, Aug 09 '17 at 06:30
@jprockbelly - ya, this text is in a html page and there are other strings in between these questions. Will update the question accordingly. Thanks — Dreams, Aug 09 '17 at 06:32
@jprockbelly - ya, since they were in different tags, I got this data through parsing. Actually, what you suggested earlier might be useful, can you elaborate on that? — Dreams, Aug 09 '17 at 06:36
@RomanPerekhrest - Sorry, can't do that. I can't share the data. — Dreams, Aug 09 '17 at 06:38

Egan Wolf · Accepted Answer · 2017-08-09T07:08:25.023

2

If you want to stay with regex, here's some solutions:

Question only: Q \d\..*?\?(?=.*(?:Ans\.)?) (finds question without answer as well)
Answer only: Ans\. .*?(?=\n\nQ \d\.)

Question and answer (one pair): Q \d\. .*?(?=\n\nQ \d\.)

Q "matches Q
(space)
\d "matches a digit
\. "matches a dot
(space)
.*? "matches everything (also new lines, you must use Single Line option), lazy matching
(?= "positive lookahead
    \n\n "matches two new lines
    Q \d\. "beginning of next question, same as before
) "end of lookahead

More about lazy (un-greedy) matching here

Demo here (improved to match last question as well)

edited Aug 09 '17 at 07:08

answered Aug 09 '17 at 06:42

Egan Wolf

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Hey Egan, thats quite helpful, can you please explain the third point. That would be helpful for me to change it according to the corner cases in my strings! Thanks – Dreams Aug 09 '17 at 06:50
1

@Tarun I added some explanation. You can use site like regex101.com to learn how regex works. – Egan Wolf Aug 09 '17 at 07:09
Thanks a lof for the help. :) – Dreams Aug 09 '17 at 07:13

Python - Regex on content between repeating strings

1 Answers1