How to Make Mistakes in Python

Chapter 1. Setup

Mise-en-place is the religion of all good line cooks…The universe is in order when your station is set up the way you like it: you know where to find everything with your eyes closed, everything you need during the course of the shift is at the ready at arm’s reach, your defenses are deployed.

Anthony Bourdain

There are a couple of ways I’ve gotten off on the wrong foot by not starting a project with the right tooling, resulting in lost time and plenty of frustration. In particular, I’ve made a proper hash of several computers by installing packages willy-nilly, rendering my system Python environment a toxic wasteland, and I’ve continued to use the default Python shell even though better alternatives are available. Modest up-front investments of time and effort to avoid these issues will pay huge dividends over your career as a Pythonista.

Polluting the System Python

One of Python’s great strengths is the vibrant community of developers producing useful third-party packages that you can quickly and easily install. But it’s not a good idea to just go wild installing everything that looks interesting, because you can quickly end up with a tangled mess where nothing works right.

By default, when you pip install (or in days of yore, easy_install) a package, it goes into your computer’s system-wide site-packages directory. Any time you fire up a Python shell or a Python program, you’ll be able to import and use that package.

That may feel okay at first, but once ...