Pythonic OOP String Conversion: .__repr__() vs .__str__()

In this tutorial series you’ll do a deep dive on how Python’s to-string conversion using the .__repr__() and .__str__() “magic methods” works and how you can implement them in your own classes and objects.

When you define a custom class in Python and then try to print one of its instances to the console (or inspect it in an interpreter session) you get a relatively unsatisfying result. The default “to string” conversion behavior is basic and lacking in detail.

By default all you get is a string containing the class name and the id of the object instance (which is the object’s memory address in CPython). That’s better than nothing, but it’s also not very useful.

The solution here is adding the .__str__() and .__repr__() “dunder” methods (some call them “magic methods”) to your class.

They are the Pythonic way to control how objects are converted to strings in different situations.

In this tutorial series I’ll do a deep dive on how Python’s to-string conversion works and how you can add it to your own custom classes.

I’ll walk you through the .__str__() and .__repr__() methods, when to use each, and some tips on how to use them in real world scenarios.

Just remember:

• The result of .__str__() should be readable.

• The result of .__repr__() should be unambiguous.

• Always add a .__repr__() to your classes. The default implementation for .__str__() just calls .__repr__(), so you get the best of both worlds.

What’s Included:

• 7 Lessons
• Video Subtitles and Full Transcripts
• Q&A With Python Experts: Ask a Question
• Certificate of Completion