Beginner's (?) Question: Attributes and __dict__

[Richard Höchenberger]

Hello, I've been looking through some code in psychopy.visual
recently; and on several occasions, I would find something like:

----------
class MyClass(ParentClass):
def __init__(self, attribute=None):
self.__dict__['attribute'] = attribute
----------

I don't understand the rationale for this; could one not simply
achieve the exact same attribute assignment via:

----------
class MyClass(ParentClass):
def __init__(self, attribute=None):
self.attribute = attribute
----------

? Why use self.__dict__ instead?

I'm sorry if this is a trivial question, but I've simply been unable
to get my head around it.

Thanks for your help,

Richard

[Jonathan Peirce]

That gets done on occasion for objects that have property setter methods
and setting the __dict__ value avoids the setter being called. Avoiding
using the setter is sometimes handy if:
- we want to avoid the extra jobs that the property setter performs
(e.g. if it will upload a texture to the graphics card and we know we'll
have to do that again a few lines later we could avoid it happening the
first time)
- we can't be sure that all the other variables are set up yet for
that parameter to do all its work

Jon

--
Jonathan Peirce
University of Nottingham

http://www.peirce.org.uk





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[Richard Höchenberger]

Great, thank you very much, this was a really helpful explanation!

All the best,

Richard