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🏆 Top 5 Python 3.15 features to start using today: 1. Lazy imports 2. New built-in `frozendict` 3. New built-in `sentinel` 4. Unpacking inside comprehensions 5. New sampling profiler Tachyon What's your top Python 3.15 new feature?

9/10/26, 6:17 pm0 reposts5 likes

Trey Hunner

@trey.io

I think my top 5 are: 1. UTF-8 as the default encoding on Windows 2. The new sentinel type 3. Unpacking in comprehensions: [*sub for sub in nested] 4. The new sampling profiler 5. pprint's new expand=True But it's hard to choose!

Rodrigo Girão Serrão 🐍🚀

@mathspp.com

What's up with the Windows UTF-8 default? Why is it such a big thing? I haven't used Windows in a while, so maybe I forgot.

Trey Hunner

@trey.io

Basically Windows has been reading/writing with an encoding of cp1252 by default for forever. Both it and utf-8 are ASCII supersets but DIFFERENT ones. Valid text in cp1252 can result in errors or emojibake in utf-8 and vice versa. It's a cross-platform mess. And once 3.14 is EOL'd it'll be done.

Rodrigo Girão Serrão 🐍🚀

@mathspp.com

How can I check for myself that the default encoding on Windows is cp1252 _without_ a Windows machine? Can you help me?

Rodrigo Girão Serrão 🐍🚀

@mathspp.com

Oh, right. Thanks for the extra context. I'm covering the UTF-8 default in my “15 days of Python 3.15”, but I just wasn't sure why you were so emphatically excited about it :D

Rodrigo Girão Serrão 🐍🚀

@mathspp.com

To learn more about each of these features, you can see examples and explanations here: mathspp.com/blog/the-5-m...

mathspp.comThe 5 most exciting new features of Python 3.15This article explains the 5 best new features of Python 3.15 with clear examples and explanations.