Is there a regexp for matching the strings (delimited by double quotes) "''" and "'''"…

Yes, the following regular expression matches the strings "''" and "'''" delimited by double quotes within a single line and ensures they balance:

import re

string = 'This is a "''" test string with "''""''"' # Example String

pattern = r'"("(?:\'{2,3})+"")"'

matches = re.findall(pattern, string)

print(matches) # Output: ['"\'\'\'\'""\'\'"']

Explanation of the pattern:

• " - matches the opening double quote
• ( - starts a capturing group
• " - matches the second double quote
• (?:\'{2,3})+ - matches one or more occurrences of either two or three single quotes, but does not capture them (the (?:) indicates a non-capturing group)
• " - matches the closing double quote
• ) - closes the capturing group
• " - matches the final double quote

Note that the above pattern assumes that there are no escaped double quotes within the string. If there are, you may need to modify the pattern to handle them.