Python: External Resources

https://en.wikibooks.org/wiki/Non-Programmer%27s_Tutorial_for_Python_3 is an extensive introduction to Python 3, and a good reference as a WikiBook. For Python 2, try here

http://www.python-course.eu/course.php is a well-done and extensive tutorial for Python 3. It also has very advanced material.

https://openstax.org/details/books/introduction-python-programming is a textbook-style Python introduction.

https://hkn.eecs.berkeley.edu/~dyoo/python/idle_intro/index.html is an introduction to Python and the IDLE environment. Good for Windows users, perhaps. Warning: it uses Python 2, so some syntax might not work in Python 3.