Difference between 'is' and '=='
maxm at mxm.dk
Wed Mar 29 12:01:18 CEST 2006
Joel Hedlund wrote:
>> There's no requirement that the socket module or
>> anything else return values using the same object that the
>> socket.AF_UNIX constant uses.
> Ouch. That's certainly an eyeopener.
> For me, this means several things, and I'd really like to hear people's
> thoughts about them.
> It basically boils down to "don't ever use 'is' unless pushed into a
> corner, and nevermind what PEP8 says about it".
Identity checks are often used for checking input parameters of a function:
if val is None:
val = 
Or if None is a possible parameter you can use your own object as a marker::
_marker = 
if val is marker:
val = 
hilsen/regards Max M, Denmark
IT's Mad Science
Phone: +45 66 11 84 94
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