On Sun, Aug 6, 2017 at 11:35 PM, boB Stepp <robertvst...@gmail.com> wrote:
>
> I see no difference in result, whether I use the @staticmethod decorator or
> not.
While a staticmethod and a function are both descriptors [1], a
staticmethod is basically a no-op descriptor. Its __get__ method
always returns its unbound callable (i.e. its __func__ attribute)
instead of returning a computed property or bound method.
Examples
>>> descr = vars(MyOtherClass)['my_other_method']
>>> descr
<staticmethod object at 0x7f558d7846d8>
>>> descr.__func__
<function MyOtherClass.my_other_method at 0x7f558d7859d8>
When accessed as an attribute of a class (i.e. the instance argument
passed to __get__ is None), a staticmethod returns just its __func__.
>>> descr.__get__(None, MyOtherClass)
<function MyOtherClass.my_other_method at 0x7f558d7859d8>
That's effectively no different from a Python 3 function. But they
diverge when accessed as an attribute of an instance. In this case the
__get__ method of a staticmethod also simply returns its __func__,
>>> descr.__get__(MyOtherClass(), MyOtherClass)
<function MyOtherClass.my_other_method at 0x7f558d7859d8>
whereas the __get__ method of a function returns a method that's bound
to the instance.
>>> func = vars(MyClass)['my_method']
>>> func
<function MyClass.my_method at 0x7f558d7858c8>
>>> func.__get__(MyClass(), MyClass)
<bound method MyClass.my_method of
<__main__.MyClass object at 0x7f558d7847f0>>
[1]: https://docs.python.org/3/reference/datamodel.html#implementing-descriptors
_______________________________________________
Tutor maillist - Tutor@python.org
To unsubscribe or change subscription options:
https://mail.python.org/mailman/listinfo/tutor
