CS50's Introduction to Programming with Python

CS50's Introduction to Programming with Python (often called CS50P) is free on two paths. Harvard publishes the whole course at cs50.harvard.edu/python, with lectures, problem sets, and solutions open to anyone, no account needed. edX hosts the same material and adds an optional verified certificate. Our 'Go deeper' button sends you to the edX listing, and we earn nothing from it: we are not in edX's affiliate program. Finish it and you can write real Python programs from the command line, with functions, file handling, exception handling, unit tests, and regular expressions: the same building blocks CS50x teaches, but slower and Python-only. Take it if you're starting from zero and want Python without the detour through C. Skip it if you already know Python basics, because CS50x's wider sweep across C, SQL, and the web will give you more. One honest limitation: CS50P stays in the terminal from the first lecture to the last. It never touches web frameworks or Django, so if web development is the goal, plan on CS50W or a framework course after it instead of treating this as the whole path. Use Harvard's site to learn for free, or use edX if you want the certificate for employers.

CS50P is one of the newer courses in Harvard's CS50 family, which has drawn nearly 5 million learners overall (source: Fortune Education, fortune.com/education).