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Re: Passing new fields to an object

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Paulo da Silva wrote:

> On 12-06-2015 17:17, Peter Otten wrote:
>> Paulo da Silva wrote:
>> 
> ...
> 
>> 
>>>>> import types
>>>>> class C(types.SimpleNamespace):
>> ...     pass
>> ...
>>>>> c = C(f1=1, f2=None)
>>>>> c
>> C(f1=1, f2=None)
>> 
> 
> Thanks for all your explanations.
> This solution works. Would you please detail a little on how it works?
> Or just point me out some readings.
> I am confused because types.SimpleNamespace seems to be a class!

It *is* a class, and by making C a subclass of SimpleNamespace C inherits 
the initialiser which does the actual work of updating the __dict__ of the C 
instance.

> From docs ...:

> class SimpleNamespace:
>     def __init__(self, **kwargs):
>         self.__dict__.update(kwargs)

The actual implementation is written in C (the language used to implement 
the CPython interpreter), but following the example in the docs you can make 
your own SimpleNamespace...

>>> class MySimpleNamespace:
...     def __init__(self, **parms): self.__dict__.update(parms)
... 
>>> m = MySimpleNamespace(a=1, b=2)
>>> m.a
1
>>> m.b
2

and when you subclass it the subclass inherits the behaviour:

>>> class C(MySimpleNamespace):
...     pass
... 
>>> c = C(x=10, y=20)
>>> c.x
10
>>> c.y
20

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Passing new fields to an object Paulo da Silva <p_s_d_a_s_i_l_v_a_ns@netcabo.pt> - 2015-06-12 16:53 +0100
  Re: Passing new fields to an object gst <g.starck@gmail.com> - 2015-06-12 09:17 -0700
    Re: Passing new fields to an object Paulo da Silva <p_s_d_a_s_i_l_v_a_ns@netcabo.pt> - 2015-06-12 19:26 +0100
  Re: Passing new fields to an object Peter Otten <__peter__@web.de> - 2015-06-12 18:17 +0200
    Re: Passing new fields to an object Paulo da Silva <p_s_d_a_s_i_l_v_a_ns@netcabo.pt> - 2015-06-12 19:34 +0100
      Re: Passing new fields to an object Peter Otten <__peter__@web.de> - 2015-06-12 21:12 +0200
        Re: Passing new fields to an object Paulo da Silva <p_s_d_a_s_i_l_v_a_ns@netcabo.pt> - 2015-06-13 04:29 +0100
  Re: Passing new fields to an object Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-06-13 01:25 +0000
    Re: Passing new fields to an object Paulo da Silva <p_s_d_a_s_i_l_v_a_ns@netcabo.pt> - 2015-06-13 04:33 +0100
    Re: Passing new fields to an object Peter Otten <__peter__@web.de> - 2015-06-13 09:49 +0200

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