PEP: Is initializing typed variable with None bad practice? (lemmy.world)

submitted 2 days 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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[-] logging_strict@programming.dev 1 points 12 hours ago

You are describing Sentinel. Recommend using attrs.NOTHING. Unfortunately, the static typing, NothingType, is in private API. Until the Python community can settle on the one Sentinel to rule them all, will stick with attrs cuz it's usually already a dependency.

You can come by my place anytime for beers and pizza. Bitching about static typing should be an Olympic sport. Or at least involve beer.

[-] solrize@lemmy.ml 1 points 10 hours ago

You might like: https://curtispoe.org/articles/what-to-know-before-debating-type-systems.html

I remember looking at attrs but not getting around to using it. These days I use dataclasses. I don't worry about this stuff too much in Python. I just notice some issues and smile. Haskell does a lot more to focus the mind, when it comes to types.

[-] logging_strict@programming.dev 1 points 8 hours ago

Thanks for the article link. Worried code too much and don't study enough.

Appreciate the reading material.

[-] logging_strict@programming.dev 1 points 8 hours ago

i'm in love with typing_extensions. Know why? I'm not on the latest greatest Python version. But want to use the usable latest features. As package author/maintainer, upgrading to the latest and greatest is not a viable option.

in py39, dataclasses lacked critical features that came out later. Especially for a fundamental structure like a dataclass, new features requiring a Python upgrade is a show stopper. On the level of a flaw. Either backport or in a separate package or i don't want to touch it. That's why use attrs and not dataclasses.dataclass

And so should we all.

There is always going to be some great features we want to use and then not being able to is not great UX. Every package that matters really must be external, except for Python features like free threading, sub-interpretors, etc.

There are always many coding languages, unfortunately jumping from one to the next is a pipe dream. So really doesn't matter what Haskell can do. Or how Rust devs all have 10 gfs.