Re Being Pythonic [ was Re: [MERGE] The eol functionality now issues a warning if a rule is configured (bug 358199) ]

[Forest Bond]

Hi,

On Sat, Apr 18, 2009 at 08:49:36AM +0100, Russel Winder wrote:
> On Fri, 2009-04-17 at 14:11 -0500, John Arbash Meinel wrote:
> 
> > ^- as a 'pythonic' thing, you should always use 'is' to compare with
> > None, so it would be:
> > 
> > if filter is None:
> >   ...
> 
> OK I am intrigued why is:
> 
> 	if filter is None : . . . 
> 
> more Pythonic than:
> 
> 	if filter == None : . . . 

It is a common idiom, in my experience, to say "if foo is None".

Otherwise, it is slightly better:

 * is does the right thing even if foo has a broken __eq__ implementation.
 * is should be faster, since it only has to compare ids, not potentially call
   __eq__, __cmp__, etc.

-Forest
-- 
Forest Bond
http://www.alittletooquiet.net
http://www.pytagsfs.org
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