Afterword – Python One-Liners


Congratulations! You’ve worked through this whole book and mastered the Python one-liner like only a few people ever will. You have built yourself a strong foundation that will help you break through the ceiling of your Python coding skills. By carefully working through all the Python one-liners, you should be able to conquer any single line of Python code you will ever face.

As with any superpower, you must use it wisely. Misuse of one-liners will harm your code projects. In this book, I compressed all algorithms into a single line of code with the purpose of pushing your code understanding skills to the next level. But you should be careful not to overuse your skill in your practical code projects. Don’t cram everything into a single line of code just to show off your one-liner superpower.

Instead, why not use it to make existing codebases more readable by unraveling their most complex one-liners? Much like Superman uses his superpowers to help normal people live their comfortable lives, you can help normal coders maintain their comfortable programmer lives.

This book’s main promise was to make you a master of Python one-liners. If you feel that the book delivered on this promise, please give it a vote on your favorite book marketplace (such as Amazon) to help others discover it. I also encourage you to leave me a note at if you encountered any problem with the book, or wish to provide any positive or negative feedback. We would love to improve the book continuously, considering your feedback in future editions, so I’ll give away a free copy of my Coffee Break Python Slicing ebook to anyone who writes in with constructive feedback.

Finally, if you seek continuous improvement of your own Python skills, subscribe to my Python newsletter at, where I release new educational computer science content such as Python cheat sheets almost daily to offer you—and thousands of other ambitious coders—a clear path to continuous improvement and, ultimately, mastery in Python.

Now that you’ve mastered the single line of code, you should consider shifting your focus to larger code projects. Learn about object-oriented programming and project management, and, most importantly, choose your own practical code projects to constantly work on. This improves your learning retention, is highly motivating and encouraging, creates value in the real world, and is the most realistic form of training. Nothing can replace practical experience in terms of learning efficiency.

I encourage my students to spend at least 70 percent of their learning time working on practical projects. If you have 100 minutes each day for learning, spend 70 minutes working on a practical code project and only 30 minutes reading books and working through courses and tutorials. This seems obvious, but most people still do this wrong and so never feel quite ready to start working on practical code projects.

It has been a pleasure to spend such a long time with you, and I highly appreciate the time you invested in this training book. May your investment turn out to be a profitable one! I wish you all the best for your coding career and hope that we’ll meet again.

Happy coding!