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PEP: Is initializing typed variable with None bad practice? (lemmy.world)
submitted 1 day ago by AstroLightz@lemmy.world to c/python@programming.dev
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For example:

class FooBar:
    def __init__(self):
        self.a: int = None
        self.foo: str = None

Is this bad practice/go against PEP guidelines or is it fine?

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[-] solrize@lemmy.ml 1 points 1 day ago

If it can be None then the type is Optional[int] or Optional[str] as the case may be. Or I guess now int | None etc. I'm used to older versions of mypy so idk if they support that alternate syntax.

Optional[int] would seem to be preferable but it turns out it's not really an option type. Like Optional[None] being None is ambiguous.

this post was submitted on 16 Mar 2026
21 points (100.0% liked)

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