On Fri, Jan 23, 2009 at 11:58 AM, Gerald Britton <gerald.brit...@gmail.com> wrote: > Hi -- Some time ago I ran across a comment recommending using <var> is > None instead of <var> == None (also <var> is not None, etc.) My own > testing indicates that the former beats the latter by about 30% on > average. Not a log for a single instruction but it can add up in > large projects. > > I'm looking for a (semi)-official statement on this, but couldn't find > one with normal googling. Can someone please send a link?
>From http://www.python.org/dev/peps/pep-0008/ , 2nd bullet under "Programming Recommendations": - Comparisons to singletons like None should always be done with 'is' or 'is not', never the equality operators. Just FYI, `is` compares object identity (pointer equality) whereas == checks for value equivalence (which causes a method call). This is why it's significantly faster. But the main reason is because it's idiomatic. Cheers, Chris -- Follow the path of the Iguana... http://rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
