It depends what you used to do with Python, really. There are a lot of users whose code didn't change from 2.x to 3.x except for the print "statements".

I replied to similar threads[0][1], reproduced here:

"""

The Python documentation is pretty cool. I frequently go to Chapter 3 (Data Model) and always learn something new reading something I had already read but didn't quite get.
The mailing list has top notch posters who are always willing to help.

The IRC channel (#python) has very helpful members who've been patient with me on more than one occasion.

Books:

Stacking the deck:

"Python Guide" - Kenneth Reitz: The bits one doesn't necessarily think about but that simplify life: virtual environments, unit test, project structure, good practices, scenarios for different kinds of applications, documentation, etc.

Doing stuff:

"Python Cookbook" (several editions by different authors, Alex Martelli and David Beazley): as the title states, it's a cookbook that shows you how to do a bunch of stuff in Python (files, network, threads, etc). This can get you "operational" in Python pretty fast.

Doing stuff well (meta):

"Writing Idiomatic Python" - Jeff Knupp:

The book comes for Python 2 and Python 3 and contrasts "harmful" and "good". Jeff Knupp also has videos showing you the process of refactoring code. He also has a blog (https://jeffknupp.com/) where he addresses many topics.

"Effective Python: 59 Specific Ways to Write Better Python" - Brett Slatkin: Pretty good book. The subtitle says it all: 59 specific ways to write better Python. (600 + pages).

"Learn Python the Hard Way" - Zed Shaw: I've read that starting out in Python. Maybe not for a 15 year Perl veteran, but this is for memo.

There's certainly some overlap in these books, but it helps to repeat a message to understand the importance of something, or to drive a point home. I didn't use virtual environments until the message was repeated enough in different ways.

Pornography:

PyCon talks. A lot of these are great.

David Beazley (a bunch of talks that are pretty cool. Still haven't finished the ones on generators but they're very good).

Brandon Rhodes (on aesthetics and design patterns (or lack thereof), and testing web applications).

Kenneth Reitz on design.

Raymond Hettinger (you'll find "Writing Beautiful Idiomatic Python" and "Beyond PEP8" most helpful).

"""

"""

Not a channel, but talks by David Beazley on Python topics are gems. High insight density. The presentation are often 60+ pages, and you can spend hours playing with each concept in every 'slide'. His talks are rabbit holes.
Raymond Hettinger tweets snippets of code that are delicious. His talks are really useful, too. Specifically, the one entitled 'Beyond PEP8' which focuses you on the impact you can have by zooming out of details and concentrate on good design.

This is something I've been using. I write code that uses a yet to be API, and ask myself and colleagues if it makes sense for them to use it.

For example, I'm writing a Python wrapper for MinIO's admin command line interfaces 'mc' and 'minio' which the Python client lacks. Put up the docs first at https://big-mama-tech.gitlab.io/bmc and asked colleagues and the MinIO folks if it's acceptable/useful before really going for parity.

"""

- [0]: https://news.ycombinator.com/item?id=15576496

- [1]: https://news.ycombinator.com/item?id=24671742