Typing, how come that :int is not ensuring int parameter?
DL Neil
PythonList at DancesWithMice.info
Thu Jun 11 17:13:52 EDT 2020
On 12/06/20 8:51 AM, zljubisic at gmail.com wrote:
> Hi,
>
> If I run this code:
> class Property:
>
> def __init__(self, var: int):
> self.a: int = var
>
> @property
> def a(self):
> return self.__a
>
> @a.setter
> def a(self, var: int):
> if var > 0 and var % 2 == 0:
> self.__a = var
> else:
> self.__a = 2
>
> if __name__ == '__main__':
> x = Property(1.5)
> print(x.a)
>
> I am getting 2.
> How come, if I have created a class with :int in order to ensure that "a" property must be an integer, that I can create an instance with float (1.5)?
You may be confusing Python with some other programming language
previously-learned. We need to 're-wire' the way your mind is working
because whilst you are not-wrong for that-language, you are not-right
for Python.
So, I'm not going to answer your question directly, but to offer you a
learning-path:-
What did mypy (or...) say, when you ran tests against the source-code?
(Typing is no use without such a testing regime!)
Have you read the docs for Typing?
- and for extra bonus-points, the numerous PEPs (proposals and accepted)
related to how Python implements Typing?
(that done, you will likely answer your own question, and accumulate
some useful learning about Python - at both the practical and
philosophical/idiomatic levels)
--
Regards =dn
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