[Python-Dev] performance of {} versus dict()

martin at v.loewis.de martin at v.loewis.de
Thu Nov 15 05:19:31 CET 2012

Zitat von Chris Withers <chris at simplistix.co.uk>:

> On 14/11/2012 21:40, Greg Ewing wrote:
>> * If the compiler were allowed to recognise builtins, it could
>> turn dict(a = 1, b = 2) into {'a':1, 'b':2} automatically.
> That would be my naive suggestion, I am prepared to be shot down in  
> flames ;-)

In general, special-casing builtins in the compiler is not possible
in Python. You cannot know statically that 'dict' really refers to
the builtin. Something may shadow the name at run-time, making dict
refer to some other callable.


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