On Apr 12, 9:46 am, John Machin <sjmac... at lexicon.net> wrote: > result = _re_comments_nc.sub(r"\1", line) s/_nc// ... that's an artifact of timing it with Non-Capture groups (?:blahblah) on the two internal groups that don't need to be capturing (results identical, and no perceptible effect on running time)