regex to match a single quote string that could contain ''' '' '''

Question

Input string could be :

- "his 'pet''s name is tom' and she is 2 years old"
- " '''' "
- " '' "
- "function('name', test, 'age')"

I want to get the single quote string from these inputs which may even contain '' inside the single quote string.

I tried negative lookahead (?!') to ignore the '' while matching.

 '.*?'(?!')

I expect output of

- 'pet''s name is tom'
- ''''
- 'name' and 'age'

do we want `pet` and `s name is tom` or `pet''s name is tom` — Işık Kaplan, May 23 '19 at 09:25
Is it because it is empty between those quotes? Because otherwise `- "function('name', test, 'age')"` this would be `name', test, 'age` — Işık Kaplan, May 23 '19 at 09:32
Not empty. It is something like a escape character ` '' ` means ` ' ` inside a string — Arun Kumar, May 23 '19 at 09:35
Possible duplicate of [regex match text in either single or double quote](https://stackoverflow.com/questions/46967465/regex-match-text-in-either-single-or-double-quote) — sahasrara62, May 23 '19 at 09:41
@prashantrana Thanks for the answer. But that doesnt solve this problem . The problem here is , there can be a two consecutive single quote within a single quote string — Arun Kumar, May 23 '19 at 09:48
Or just `r"'[^']*(?:''[^']*)*'"`, see [demo](https://regex101.com/r/mwmbvE/1) — Wiktor Stribiżew, May 23 '19 at 10:01
Glad it worked for you. Please consider also upvoting if my answer proved helpful to you (see [How to upvote on Stack Overflow?](http://meta.stackexchange.com/questions/173399/how-to-upvote-on-stack-overflow)) . — Wiktor Stribiżew, May 24 '19 at 07:30

Alaa Aqeel · Answer 1 · 2019-05-23T10:15:41.223

0

r"'(.+?)'" To get the single quote string

import re 

tx = "his 'pet''s name is tom' and she is 2 years old"

print(re.findall(r"\'(.+?)\'",tx)) 
#output :  ['pet', 's name is tom']

edited May 23 '19 at 10:15

answered May 23 '19 at 10:08

Alaa Aqeel

I think that to fullfill the request you should replace the "+" with a "*" inside of your regex, currently you are getting two matches, while you should get only one – DLM May 23 '19 at 10:57
same thing , to get only one, delete this `?` out this `["pet''s name is tom"]` – Alaa Aqeel May 23 '19 at 11:19

score 0 · Accepted Answer · answered May 23 '19 at 10:56

0

I think you may achieve that with

r"'[^']*(?:''[^']*)*'"

Explanation

' - a single quotation mark
[^']* - 0+ chars other than single quotation mark
(?:''[^']*)* - zero or more repetitions of
- '' - two single quotation marks
- [^']* - 0+ chars other than single quotation mark
' - a single quotation mark

answered May 23 '19 at 10:56

Wiktor Stribiżew

@ArunKumar Glad it worked for you. Please also consider [upvoting the answer](http://meta.stackexchange.com/questions/173399/how-to-upvote-on-stack-overflow) if it turned out useful for you. – Wiktor Stribiżew May 23 '19 at 19:52

2 Answers2