What Exactly Is the Zen of Python?

The Zen of Python is a collection of 19 aphorisms that capture the guiding principles behind Python’s design. You can display them anytime by running import this in a Python REPL. Tim Peters wrote them in 1999 as a joke, but they became an iconic part of Python culture that was even formalized as PEP 20.

By the end of this tutorial, you’ll understand:

• The Zen of Python is a humorous poem of 19 aphorisms describing Python’s design philosophy
• Running import this in a Python interpreter displays the complete text of the Zen of Python
• Tim Peters wrote the Zen of Python in 1999 as a tongue-in-cheek comment on a mailing list
• The aphorisms are guidelines, not strict rules, and some intentionally contradict each other
• The principles promote readability, simplicity, and explicitness while acknowledging that practicality matters

Experienced Pythonistas often refer to the Zen of Python as a source of wisdom and guidance, especially when they want to settle an argument about certain design decisions in a piece of code.
In this tutorial, you’ll explore the origins of the Zen of Python, learn how to interpret its mysterious aphorisms, and discover the Easter eggs hidden within it.

You don’t need to be a Python master to understand the Zen of Python! But you do need to answer an important question: What exactly is the Zen of Python?

In Short: It’s a Humorous Poem Listing Python Philosophies

According to the Python glossary, which contains definitions of popular terms related to this programming language, the Zen of Python is a:

Listing of Python design principles and philosophies that are helpful in understanding and using the language. The listing can be found by typing “import this” at the interactive prompt. (Source)

Indeed, when you type the indicated import statement into an interactive Python REPL, then you’ll be presented with the nineteen aphorisms that make up the Zen of Python:

>>> import this
The Zen of Python, by Tim Peters

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than *right* now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!

The byline reveals the poem’s author, Tim Peters, who’s a renowned software engineer and a long-standing CPython core developer best known for inventing the Timsort sorting algorithm. He also authored the doctest and timeit modules in the Python standard library, along with making many other contributions.

Take your time to read through the Zen of Python and contemplate its wisdom. But don’t take the aphorisms literally, as they’re more of a guiding set of principles rather than strict instructions. You’ll learn about their humorous origins in the next section.

How Did the Zen of Python Originate?

The idea of formulating a single document that would encapsulate Python’s fundamental philosophies emerged among the core developers in June 1999. As more and more people began coming to Python from other programming languages, they’d often bring their preconceived notions of software design that weren’t necessarily Pythonic. To help them follow the spirit of the language, a set of recommendations for writing idiomatic Python was needed.

The initial discussion about creating such a document took place on the Python mailing list under the subject The Python Way. Today, you can find this conversation in the official Python-list archive. If you look closely at the first message from Tim Peters in that thread, then you’ll notice that he clearly outlined the Zen of Python as a joke. That original form has stuck around until this day:

Clearly a job for Guido alone – although I doubt it’s one he’ll take on
(fwiw, I wish he would too!). Here’s the outline he would start from,
though <wink>:

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren’t special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one– and preferably only one –obvious way to do it.
Although that way may not be obvious at first unless you’re Dutch.
Now is better than never.
Although never is often better than right now.
If the implementation is hard to explain, it’s a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea – let’s do more of those!

There you go: 20 Pythonic Fec^H^H^HTheses on the nose, counting the one I’m
leaving for Guido to fill in. If the answer to any Python design issue
isn’t obvious after reading those – well, I just give up <wink>. (Source)

The wink and the playful way of self-censoring some toilet humor are clear giveaways that Tim Peters didn’t want anyone to take his comment too seriously.

Eventually, these nearly twenty theses got a proper name and were formally codified in a Python Enhancement Proposal document. Each PEP document receives a number. For example, you might have stumbled on PEP 8, which is the style guide for writing readable Python code. Perhaps as an inside joke, the Zen of Python received the number PEP 20 to signify the incomplete number of aphorisms in it.

To win your next argument about what makes good Python code, you can back up your claims with the Zen of Python. If you’d like to refer to a specific aphorism instead of the entire poem, then consider visiting pep20.org, which provides convenient clickable links to each principle.

And, in case you want to learn the poem by heart while having some fun, you can now listen to a song with the Zen of Python as its lyrics. Barry Warsaw, another core developer involved with Python since its early days, composed and performed this musical rendition. The song became the closing track on a special vinyl record entitled The Zen Side of the Moon, which was auctioned at PyCon US 2023.

Okay. Now that you have a rough idea of what the Zen of Python is and how it came about, you might be asking yourself whether you should really follow it.

Should You Obey the Zen of Python?