[issue11740] difflib html diff takes extremely long

Changes by Benjamin Peterson : -- resolution: -> duplicate status: open -> closed superseder: -> dreadful performance in difflib: ndiff and HtmlDiff ___ Python tracker ___

[issue11740] difflib html diff takes extremely long

Filip Gruszczyński added the comment: The culprit seems to be Differ._fancy_replace. There is a nasty quadratic loop there, that has pretty complex internal code. I have done a quick a fix, that makes example run below a second at the expense of not calling _fancy_replace for longer chunks an

[issue11740] difflib html diff takes extremely long

ysj.ray added the comment: Reproduced in 3.3 -- components: +Library (Lib) -None nosy: +ysj.ray versions: +Python 3.1, Python 3.2, Python 3.3 ___ Python tracker ___

[issue11740] difflib html diff takes extremely long

Changes by Filip Gruszczyński : -- nosy: +gruszczy ___ Python tracker ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.

[issue11740] difflib html diff takes extremely long

New submission from Michael O'Rourke : If you try to difference the attached files with difflib and a html difference it take 10 minutes or more. In comparison other differencing tools like windiff and araxis merge will show the diff within a second. Example code I'm using is: sourceText = o