ALL of Python 3.13's MAJOR typing changes

Python 3.13 released this week, and there was so much to talk about, I didn't really have time to discuss its new typing features! This video rectifies that, by giving them some time to shine.

0:00 - Intro
0:38 - Default values for TypeVars [1-2]
3:08 - The @deprecated decorator [3]
5:21 - ReadOnly values for TypedDicts [4-5]
7:24 - Better type predicates with TypeIs [6-7]
9:55 - Outro

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If you have any questions, don't hesitate to ask in the comments! I'll try and answer as soon as I can, providing someone else hasn't already done so.

#python #coding #howto

[maleldil]

Why do you use the old generics syntax for these examples? IMO, it doesn't much sense to use the old syntax when the new one is available. I understand using it for more general videos, so they apply to a wider public, but not here. Regardless, I'd appreciate it if you could show both versions anyway.

Anyway, great video. Hopefully pyright implements the new typing stuff soon.

[EngineerNick]

Thankyou this was a great summary and demo :)

[Heavy_Lvy]

7:16 probably the extension is using a older version of pyright or mypy. The extension won't use the pyright/mypy version installed on your environment.

[fmitchella]

Thanks for this. I'm just now catching up on 3.13's features.

A video on support for Protocols would be appreciated. My statically typed brain still can't quite fit itself around Python's protocols using duck typing, and compile-time or run-time predicates verifying that a class conforms to a Protocol would make using Protocols feel like black magic (or pure superstition).

[aungthuhein]

"Dynamic typing is cool, bro!" Now spend years correcting that shit.

[chrism]

Is it possible to back port the new repl to use it with older python versions?

[murphygreen]

What's the benefits of ReadOnly over Final?

[solojazzz]

wait I thought that python 3.13 was about using 'type' as a keyword instead of TypeVar