Python Regex: a robust way to use Regex for mix EOL-Replacement (CR, LF, CRLF) [duplicate]
Solution 1:
Regex to find any LF that is not part of a CRLF:
(?<!\r)\n
Regex to find any CR that is not part of a CRLF:
\r(?!\n)
Thus Regex to find any non-CRLF lineEnding:
((?<!\r)\n|\r(?!\n))
You can simply replace that with \r\n to fix them all to be CRLFs.
This is using the "Negative Lookbehind" functionality:
(?<\!a)bmatches a "b" that was not preceded by an "a".
and the "Negative Lookahead" functionality:
a(?\!b)matches an "a" that is not followed by a "b".
Further documentation here: https://www.regular-expressions.info/lookaround.html