when you set an attribute of an object, python secretly calls that
objects __setattr__ method.
class test:
def __setattr__(self, attr_name, attr_value):
print self, attr_name, attr_value
self.__dict__[attr_name] = attr_value # do what the original
__setattr__ method does.
test().fred = 'george' # prints <test instance ...> fred george
Miguel Galves wrote:
> Hello,
>
> I`m starting to learn python, and I hava a very good background in Java
> and C/C++ programming. I was reading Dive into python chapter about
> OO and I saw that in python we can do the following:
>
> class Person:
> pass
>
> joe = new Person()
> joe.name = "Joe"
> joe.age = 13
>
> It seems that it is possible to add attributes to any object instance
> in run time, as in Javascript. It seems to me that it can be a source
> of errors. One that come in my mind is the follwing:
>
> class Person:
> name = ""
>
> joe = new Person()
> joe.nome = "Joe"
>
> The code above adds an attribute called nome, but the programmer may think
> it's name.
>
> What is the real interest of this feature ? Is there a way to block this
> kind of error ?
>
> Thanks,
>
> Miguel
> --
> Miguel Galves - Engenheiro de Computação
> Já leu meus blogs hoje?
> Para geeks http://log4dev.blogspot.com
> Pra pessoas normais
> http://miguelgalves.blogspot.com
>
> "Não sabendo que era impossível, ele foi lá e fez..."
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