CS50's Introduction to Programming with Python Review (2026)

Who it's for

What you'll learn: the 11 courses

1. Lecture 0: Functions, VariablesWriting and running Python, input and output, strings, integers, floats and defining your own functions.
2. Lecture 1: Conditionalsif, elif and else, Boolean expressions and match statements.
3. Lecture 2: Loopswhile and for loops, lists, dictionaries and iterating over data.
4. Lecture 3: ExceptionsHandling errors with try and except, and validating user input.
5. Lecture 4: LibrariesModules, the standard library, pip packages and calling web APIs.
6. Lecture 5: Unit TestsTesting your own functions with assert and pytest.
7. Lecture 6: File I/OReading and writing text and CSV files, and working with images.
8. Lecture 7: Regular ExpressionsPattern matching to validate and extract data from text.
9. Lecture 8: Object-Oriented ProgrammingClasses, objects, methods, properties and inheritance.
10. Lecture 9: Et CeteraExtra language features such as sets, type hints, comprehensions and generators.
11. Final ProjectAn original Python program of your own design, built with the tools from the course.

Skills you'll practise

CS50’s Introduction to Programming with Python is the best free Python course for beginners who want a real challenge. Known as CS50P, it is Harvard’s introductory programming course taught by David J. Malan, offered through edX and as free OpenCourseWare. Harvard lists it as roughly 9 to 10 weeks at 3 to 9 hours a week. Score at least 70% on every problem set and the final project, and you earn a free CS50 certificate. It is harder than Python for Everybody, and that is the point.

The course spends ten lectures on core Python, then adds the habits working programmers rely on: handling exceptions, writing unit tests, using regular expressions and organizing code into classes. Compare it with the rest of our best Python courses or visit the Python subject hub.

Is CS50 Python worth it in 2026?

Yes, for beginners who like to be stretched. It costs nothing, the teaching is excellent, and it teaches testing and regular expressions that cheaper or gentler courses skip. It is less worth it if you need hand-holding or a brand-name job certificate.

The lectures are polished and fast. Malan builds each idea live in code, makes mistakes on purpose and fixes them, so you see how a programmer actually thinks. Shorter videos then cover single topics if you need a second look.

The problem sets are where the learning happens. Each week has several small programs, and the course’s check50 tool runs automated tests against your code. Either your program handles the edge cases or it does not. That honesty is valuable, but it can also leave a beginner stuck on one problem for an evening.

When the answer flips

• You have never coded and get discouraged easily: Python for Everybody covers similar basics at a gentler pace.
• You want many finished projects: 100 Days of Code gives you 100 builds instead of weekly problem sets.
• You need Python for data work: IBM Python for Data Science, AI & Development reaches pandas and NumPy sooner.
• You want automation for your office job: Automate the Boring Stuff is shorter and more practical.

How much does CS50 Python cost?

The course and the CS50 certificate are free. You only pay if you want an edX verified certificate or the paid Harvard professional certificate program that bundles CS50P with CS50x.

The free route uses Harvard’s own site, a GitHub account to submit work, and the browser-based coding environment CS50 provides. The CS50 certificate page states the rule plainly: at least 70% on each problem and on the final project. The edX verified certificate is optional, and its price varies, so check edX before paying.

For most learners the free CS50 certificate is enough. It shows the same work as the paid one. Our free certificates hub lists other courses that award certificates at no cost, and the edX review explains how verified tracks work.

How hard is CS50 Python?

It is the hardest beginner course in our Python batch. No experience is required, but the problem sets expect you to read documentation, test edge cases and debug on your own. Plan on the upper end of Harvard’s 3 to 9 hours a week.

The difficulty curve has two steep points. Lecture 4 on libraries asks you to install packages and call a web API. Lecture 7 on regular expressions is where many learners slow down, because the patterns are terse and the tests are strict. Object-oriented programming in lecture 8 is gentler if you did the earlier problems carefully.

The final project is open-ended, with firm rules. Your program needs a main function plus at least three more functions, each tested with pytest, and a video of no more than three minutes. Pick something small that you will actually use. A finished tool beats an ambitious idea left half-done.

CS50 Python vs alternatives

CS50P wins on rigor and price. Its rivals win on gentleness, project volume or career focus.

A strong free path is Python for Everybody on py4e.com, then CS50P. You get the gentle start and the rigor without paying for either. Our freeCodeCamp review covers the other major free option.

What can you do after CS50 Python?

You can write tested, multi-file Python programs, validate input with regular expressions and model data with classes. That foundation carries well into web development, data work or a deeper computer science course.

Next steps depend on the goal. For a computer science base, Harvard’s CS50x covers C, algorithms, SQL and web basics. For data, move to pandas through IBM Data Science. For a developer job, read our software engineer career guide and build two or three projects beyond your final project.

CS50 Python FAQ

Alternatives