[FIXED] regex to match a single quote string that could contain ''' '' '''

Issue

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'

Solution

I think you may achieve that with

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

See the regex demo

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

Regex graph:

Answered By - Wiktor Stribiżew