Note: there are currently two versions of Python that are commonly taught and used – Python 2, and Python 3. Python 3 is the most recent version, but for a variety of reasons Python 2 still is fairly popular among many developers despite end-of-life in 2020.
If you're not sure which version to pick, my recommendation would be to pick the resource which looks like the best fit for you, and just use whatever version they're recommending. Luckily, the differences between the two are very minor (at least from the perspective of the beginner), so there's really no difference if you learn using Python 2 vs Python 3.
That said, when working on your own programs, I would always pick Python 3 unless you have good reason to otherwise. The Python community, with the exception of a few holdouts, is moving towards Python 3 and abandoning Python 2.
The companion book can be found here. The course is designed for beginners, part of a 2-part series, is self-paced, and has an emphasis on computation and data science.
A gentler version of the above.
For beginners; requires registration.
Requires some prior programming experience; focuses on object-oriented programming.
Allows a free 14-day trial, but later requires payment. Interactive resources: LearnPython An interactive online guide that teaches basic Python. Try Python Another interactive online guide. Video tutorials: N/A
A comprehensive introductory text on Python, focusing on teaching computer science fundamentals and problem-solving skills through Python. Suitable for beginners.