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Pydon'ts

Write elegant Python code

A series of articles that teaches you how to make the best use of the core Python features. The Pydon'ts are available as an e-book that you can read for free below.

Deep unpacking (or nested unpacking) provides a more powerful way for you to write assignments in your code. Deep unpacking can be used to improve the readability of your code and help protect you against unexpected bugs. Learning about deep unpacking will also be very important in order to make the most out of the structural matching feature that is to be introduced in Python 3.10.

Recursion is a technique that you should have in your programming arsenal, but that doesn't mean you should always use recursion when writing Python code. Sometimes you should convert the recursion to another programming style or come up with a different algorithm altogether.

All Python objects can be used in expressions that should return a boolean value, like in an if or while statement. Python's built-in objects are usually Falsy (interpreted as False) when they are “empty” or have “no value” and otherwise they are Truthy (interpreted as True). You can define this behaviour explicitly for your own objects if you define the __bool__ dunder method.

Python's str and repr built-in methods are similar, but not the same. Use str to print nice-looking strings for end users and use repr for debugging purposes. Similarly, in your classes you should implement the __str__ and __repr__ dunder methods with these two use cases in mind.