#python #virtualenv

A useful question for understanding software tools is to peel back a layer of abstraction and ask what the thing underneath is. For example:

• On a computer, text is a sequence of numbers (and a system to interpret that as letters).
• An HTTP request is a blob of text with a particular format.
• An interpreter (like the Python or Ruby interpreters) is a program, whose function is to execute other programs.

Knowing this sort of thing is useful when the abstractions break (e.g. when you open a text file with the wrong encoding) or when thinking about the fundamental contours of a system's possibility space. For example, if you know that programs can be configured with environment variables and CLI flags, knowing that the Python interpreter is a program means you know where to start looking if you need to configure it.

While there are many, many articles on the internet explaining how and why to use them, there's less information about what a Python virtual environment (or “virtualenv”) is. Luckily for us, it ends up not being very difficult to investigate.