Using pyenv to manage multiple python versions & virtual environments

pyenv.md

There is a lot of confusing information about virtual environments in python out there, in part because the tool chain has evolved over many years.

I decided to follow the advice of Real python and The hitchhiker's guide to python and manage both multiple python versions and multiple virtual environments with pyenv

Installing pyenv on MX Linux

I used homebrew to install pyenv on my linux machine running MX 23.1 Libretto.

brew update
brew install pyenv

Afterwards, I executed the following code to add three lines to my ~/.bashrc file, as recommended on the pyenv README page.

echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.bashrc
echo 'command -v pyenv >/dev/null || export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(pyenv init -)"' >> ~/.bashrc

Installing python with pyenv

Next, I used pyenv to install the latest release version of python, version 3.12.1 (at the time of writing).

Troubleshooting

I ran into the issue reported here, preventing me from installing python with pyenv (see below). It turns out that brew masks the system's pkg-config, intefering with the compilation of python.

I unlinked pkg-config with the following command, and the installation succeeded:

brew unlink pkg-config

Installing python version 3.12.1

First, I listed the (many) python versions pynev is aware of:

pyenv install --list

and then installed the version of my choice:

pyenv install -v 3.12.1

Setting the default python version

Finally, I set my new python installation as the default version:

pyenv global 3.12.1

Creating and using virtual environments

To make using virtual environments with pyenv easier, I installed the pyenv-virtualenv plugin:

brew install pyenv-virtualenv

Creating a first virtual environment

The pyenv virtualenv command creates a new virtual environment for the specified python version (e.g. 3.12.1).

pyenv virtualenv 3.12.1 rango

All virtual environments created in this way are stored in the same location, by default the ~/.pyenv/versions folder:

ls ~/.pyenv/versions/

Activating a virtual environment

The following command activates my new rango virtual environment:

pyenv activate rango
python --version  # 3.12.1

and the equivalent command deactivates it:

pyenv deactivate rango

Using virtual environment in VS Code

To use my virtual environment in the VS Code IDE:

1. Open VSCode preferences (Ctrl + ,)
2. Search for venv.
3. Add ~/.pyenv to the “Venv Path” text box.

Afterward, I can choose the python interpretor from the rango virtual environment (once I have created a python file) by clicking on the python version in the bottom right of the vscode window.