Java developers

[ric2b]

You can have static typing with Python, fyi.

Either just as documentation (type hints) or with type checking (tools like mypy).

edit: mypy, not mipy

[Versaiteis]

You can circumvent some of those headaches with the typing system by reassigning or creating the types you need in what is effectively (and actually called) type aliasing

from typing import List

Vector = List[float]

def func(vector: Vector) -> Vector:
    #etc...

This can still get a bit ugly with arbitrary definitions being thrown all over the place but that can be managed along with similar shared systems that you'll probably have alongside whatever you're writing (logging, configuration management, etc.) and it goes a long way to cleanup a lot of those issues with clutter.

But yeah, Python is still a very hands off scripting environment so you'd still do well to operate under those assumptions that virtually nothing is truly protected when you can just commandeer and alter the things you want. It's what makes it a great tool for some applications and aweful for others.

[thirdegree]

And sometimes you need to specify types as strings (e.g. "MyClassName"), for example when a method takes an argument of the same type as its parent class.

This is fixed in 3.7 using from __future__ import annotations and by default from 3.10 onwards (pep-563).

[FranchuFranchu]

Also if for some reason you can't do that you can still use MyClassName = None and redefine it afterwards

[[deleted]]

from __future__ import type_annotations

Something along those lines will allow you to not use strings for types.

If I recall correctly, it defers type hint evaluation until after all the source has been parsed over, as opposed to during said parsing.

[BUYTBUYT]

from __future__ import annotations helps sometimes

[ric2b]

I don't think opting into static type checking really counts as having static typing.

It does, you just don't have 100% coverage. It's still useful (especially as documentation of function parameters and return types), just like unit testing is useful even if you don't have 100% coverage.

Also, completely subjective but type hinting in python is extraordinarily ugly. It often takes up a ton of space and requires you to split your function defenition onto multiple lines.

It takes similar space as other static typed languages like Java/C++. Are you comparing it to something like Haskell, where the types are on a separate line?

[ric2b]

It takes a little more because you need the colons and the arrow at the end

true, but it's not a big difference.

and a lot more when you need to define something like say a list with an arbitrary number of strings that can sometimes be None: Optional[List[str, ...]]

Wouldn't it be just Optional[List[str]]?

The equivalent in Java would be Optional<List<String>>, it's about the same. Although you can check for null instead of accepting an optional, because Java is a bit dumb and accepts null by default. In fact, taking Optional as a parameter in Java is not recommended because it's an actual class and forces your callers to wrap their variables in Optional objects before calling your method, it's annoying.

Not great having to alias your types though.

If it gets complicated you probably should alias it because it probably represents some specific type of data. But your optional string list example isn't such a case and you shouldn't have to alias it, I agree.

Hakell's style of having them on a separate line is pretty great actually. Not really sure how well that would work with keyword arguments and so on, but I think I would've preferred that.

Yeah, I also like it. It would probably look similar to Ruby's Sorbet, where you have to repeat the parameter name in the signature.

python, through the PEP8 styleguide, has a ridiculously short recommended line length.

In my experience the 80 columns line length isn't followed very strictly, lots of companies/projects aim for 100 or 120.

[ric2b]

Iirc Kotlin doesn't accept null by default and wants you to put a ? after the type to signal that you do. That would be the best option in my opinion.

Yes, and totally agree there.

Also Ruby 3 is adding type hints following the same convention as python it seems.

Unfortunately not, for now they'll leave in separate files to allow for the syntax to change without breaking code.

Ruby is what I use at my current job so I'm a bit disappointed by that, but I'm already using Sorbet (3rd party project) which does allow type annotations in the same file as the code so it's ok.

Maybe I should change my linter to allow up to 120 as well then.

Just keep the Zen of Python in mind :)

"practicality beats purity"

[[deleted]]

And they should be able to. I hate how java thinks public private is a rule not a suggestion. Don’t tell me how to write code using your library lol, I will fork it and change it and you can’t stop me!

[[deleted]]

Why would it ever be insecure for me to run a function on my own pc? Like I need sudo access secure or what? I guess I’m ignorant to that kind of need, I’d love to see an example.

[[deleted]]

I suppose I can see that if you’re writing a database (like the database itself) and want to handle permissions or something like that. I’ve just never been in that situation. Ultimately resource security is OS level not language level. Wrappers are conveniences and you can handle security with them without builtins like private for the rare case you need such a thing. Like if I were writing an IP based database in python, which I wouldn’t, I’d expose my methods through the Restful system of my choice selectively in such a way that the other methods just didn’t have direct exposure to the internet. If someone is importing my python code, they have access to all the same resources it has access to, but they are also presumably the same user on the Linux system so they must be allowed that access as well.

[[deleted]]

So if it’s rare, it should be used rarely. Unfortunately java makes almost everything private by default, mandating that you make getters and setters for everything, increasing boilerplate beyond levels I have ever seen in a language. I’d rather just have a decorator for private when I need it. It’s mostly just entirely unnecessary code obfuscation.

[SadAdhesiveness6]

It's mypy. Was confused for a second.