NEW generic / alias syntax for python 3.12 (PEP 695) (intermediate) anthony explains

Подписаться 39 тыс.

Просмотров 10 тыс.

50% 1

today we go over the new syntax added in python 3.12 for generics and type aliases!
- what's new in python 3.12? • python 3.12 release hi...
- TypeVarTuple and variadic generics: • python variadic generi...
- ParamSpec and decorator typing: • decorator typing (PEP ...
playlist: • anthony explains
==========
twitch: / anthonywritescode
dicsord: / discord
twitter: / codewithanthony
github: github.com/asottile
stream github: github.com/anthonywritescode
I won't ask for subscriptions / likes / comments in videos but it really helps the channel. If you have any suggestions or things you'd like to see please comment below!

Наука

Опубликовано:

13 июл 2024

Ссылка:

Скачать:

Готовим ссылку...

Добавить в:

Мой плейлист

Посмотреть позже

Комментарии : 50

@MostWantedracer 8 месяцев назад

Here's to Anthony: The only guy who's not afraid of opening a browser window in front of you *while recording* and typing something that starts with "P".

@csanadtemesvari9251 8 месяцев назад

Incognito mode exists

@anthonywritescode 8 месяцев назад

it does exist -- but this is just raw google chrome with history on

@calebparks8318 8 месяцев назад

For me "p" directs to "pytorch".

@hamzadlm6625 Месяц назад

@@csanadtemesvari9251 either you don't know what incognito looks like, or you dare to assume he doesn't know that it exists, both are unrecoverably stupid

@unvergebeneid 8 месяцев назад

Well I don't know if I like this new syntax but I know I've always hated the weirdly redundant TypeVar syntax.

@BenjaminWheeler0510 8 месяцев назад

why didn't they just use the industry standard of ? oh well

@Redstoner237Channel 8 месяцев назад

@@BenjaminWheeler0510 wasnt industry standard when python first introduced typing. Now they have to keep with it for backwards compatibility

@anthonywritescode 8 месяцев назад

that's simply not true -- c# generics were 2005, java generics were 2004, c++98 had templates (and some compilers back until 1991 had some form of templates) all with angle brackets long before python typing was even an idea (mypy first released in 2009, python 3.0 syntax was 2008, the typing module was 2015)

@rexase 8 месяцев назад

this is great, very Rust-like I think they should use for generics

@rosmelylawliet3919 8 месяцев назад

i would have loved that, as `[...]` is already used for indexes/keys, whereas `` is invalid. i would need to check the pep to see the reason why they went this way, there's likely a reason

@anthonywritescode 8 месяцев назад

my understanding is there's already usage of `[...]` in python so when generics were originally added it was "natural" with the syntax -- whereas angle brackets are only used for comparisons and would have needed a bigger lift to adopt them as a syntax construct maybe if they went back today and redid everything without regards for backwards compatibility it'd be with angle brackets -- but it'd be too much of a lift to just do it now

@amirongoogle4795 8 месяцев назад

if it is possible, please make a video about variants; thank you.

@mrswats 8 месяцев назад

Good stuff, as per usual!

@hamzadlm6625 Месяц назад

Thank you for sharing

@AceofSpades5757 8 месяцев назад

So cool! Hype 🎉

@BrunoBeltran 8 месяцев назад

Maybe I've been brainwashed by C++ but I find the new syntax very readable and natural.

@bradb4143 8 месяцев назад

Looks a lot like Go generics syntax, thanks for the video!

@workflowinmind 8 месяцев назад

5:08 That's the most logical syntax to me, what would you have preferred?

@qexat 8 месяцев назад

for someone who uses typevars a lot this syntax kinda grew in me tbh…

@ismailbello513 6 месяцев назад

Hi Anthony, nice video as always! would be nice to hear your thoughts on typing.Annotated!

@anthonywritescode 6 месяцев назад

tbh I haven't really used it, I steer far away from runtime annotations

@iliya-malecki 8 месяцев назад

why is it def f[T: (str, bytes)](x:T):... and not def f[T: str | bytes](x:T):...? i tried the version that is more intuitive to me and it works. Is it not guaranteed to work? whats the deal with the whole thing?

@anthonywritescode 8 месяцев назад

"it works" -- nothing is checking these in python itself -- it would be up to the typechecker to validate those it's a tuple because that's how it is specced -- yours is different saying that T must be a subclass of a union of int and str -- which is impossible because there exists no class which is a subclass of both int and str (so the typechecker should produce an error)

@iliya-malecki 8 месяцев назад

@@anthonywritescode No no when i say "it works" i mean pyright in strict mode doesnt complain. Also, "a subclass of both int and str" is an intersection type (which i know doesnt exist yet), not a union, so doesnt it mean that T is a subclass of a Union[int, str] if it is a subclass of either int or str?

@anthonywritescode 8 месяцев назад

youtube deleted my response because it was too long -- I misspoke about this and got it backwards but they still mean different things (the union can be satisfied by a union whereas the tuple has distinct bounds) an example: ``` from collections.abc import Sequence def f[T: int | str](a: Sequence[T], b: Sequence[T]) -> list[T]: return [*a, *b] def g[T: (int, str)](a: Sequence[T], b: Sequence[T]) -> list[T]: return [*a, *b] f([1], ['2']) f([1], [2]) f(['1'], ['2']) # g([1], ['2']) not allowed: must be a uniform list g([1], [2]) g(['1'], ['2']) ```

@iliya-malecki 8 месяцев назад

@@anthonywritescode wow, this is massive! This essentially solves the "cat in the list of animals" problem that plagues, among others, typescript. Another huge victory! Can we celebrate or should we wait for intersection types first? Also, I would love a video on intermediate/advanced typing tricks, do you plan on making one? Please do, love your content :)

@anthonywritescode 8 месяцев назад

tbf this already exists but the syntax changes how it works -- you can do the same thing with TypeVar("T", int, str) vs TypeVar("T", bound=int | str) I do occasionally do some tricks like this but they're not always so universally applicable -- maybe I'll cover this one though

@BenjaminWheeler0510 8 месяцев назад

I like types, yes I do. I like types, how about you?

@yorailevi6747 8 месяцев назад

At this point, almost all languages are functionally the same with different syntax. everything but maybe rust which can be emulated with robust linter in cpp.

@NicolasChanCSY 8 месяцев назад

This change does not look very intuitive... In addition, now the function signatures become so long when we add type hints, how should we cope with the 80-ish characters per line rule of PEP8? (Yes, I think 80-ish is still better even when we have much wider screens these days)

@anthonywritescode 8 месяцев назад

it's familiar if you've worked with generics in other languages -- though they tend to use angle brackets instead

@skela3152 8 месяцев назад

You can have multiline function signatures with each argument on it's own line which should eliminate the problem unless you have very, very long function, argument, and type hint names.

@fuadnafiz98 8 месяцев назад

How do you remember all the syntaxs without any code completion or autosuggesions? 🙄

@timbrap4693 8 месяцев назад

Some people are just built different

@juniorceccon 8 месяцев назад

That kind of skill is built over time. Eventually, you get used to it.

@IonizedComa 8 месяцев назад

its easier to do it with python because it's an easily read language, i'm able to do it with C as well. But Java and C++ I have problems remembering most things. Also depends on which language you use often

@ericng8807 8 месяцев назад

3:00 AI grifters fuming right now

@calebparks8318 8 месяцев назад

Hurray! Good riddance to "from ___future___ import annotations."

@blanky_nap 8 месяцев назад

after watching this video i have only one question: python wtf are you doing?

@float32 8 месяцев назад

I’m thinking of moving to swift. If I wanted all this complexity, I would use a compiled language and get 10x the performance, so might as well.

@yomajo 8 месяцев назад

For most of my usecases I use built in types or my own classes for typehints, and have no idea what a Generic is... This seems like a woke trend in python. A shame.

@lonterel4704 8 месяцев назад

@@float32but swift is not good outside of macos. What do you use Python for?

@MrYevelnad 8 месяцев назад

IDK why python implemented generics when its a dynamically typed language. I'm kinda hyped when I first knew this and it is much simpler to implement in 3.12. I play with it a bit and came to a conclusion that it is pretty much useless in python.

@anthonywritescode 8 месяцев назад

it's not for the runtime, it's for type checkers

@mailoisback 8 месяцев назад

No performance gain, just useless syntax stuff that is littering Python.

@anthonywritescode 8 месяцев назад

technically this performs better than TypeVar(...) calls since it's all lazily evaluated -- and 3.12 did improve performance quite a bit for basically everything not defending the syntax in any way -- just correcting your baseless complaints