Setting Up a Python Development Environment with pyenv, Poetry, Black, mypy, and pre-commit

Python offers a rich ecosystem of libraries and tools, but managing multiple interpreter versions and dependencies can quickly become chaotic for data scientists and developers.

Python Development Environment

Interpreter: Choose and install the desired Python version, then place it under a managed environment.

If you need to switch between different Python versions or conflicting third‑party modules, curl https://pyenv.run | bash installs pyenv , which provides version isolation.

After installation, add the following lines to .bashrc or .zshrc so that pyenv becomes available:

export PATH="~/.pyenv/bin:$PATH"

eval "$(pyenv init -)"

eval "$(pyenv virtualenv-init -)"

Restart the terminal, then you can install any Python interpreter, e.g., pyenv install 3.7.5 and set it as the global default with pyenv global 3.7.5.

On Ubuntu, install required system libraries before building Python:

sudo apt-get install build-essential libsqlite3-dev sqlite3 bzip2 libbz2-dev zlib1g-dev libssl-dev libgdbm-dev libgdbm-compat-dev liblzma-dev libreadline-dev libncursesw5-dev libffi-dev uuid-dev

Use pyenv install --list to view all available versions.

Dependency Management

Poetry is recommended for managing project dependencies and virtual environments. Install it with:

curl -sSL https://raw.githubusercontent.com/sdispater/poetry/master/get-poetry.py | python

Configure Poetry to create virtual environments inside the project directory: poetry config settings.virtualenvs.in-project true Create a new project and add required packages:

poetry new dsexample

cd dsexample

poetry add pandas=0.25 fastapi --extras all

poetry add tf2-utils --git [email protected]:Shawe82/tf2-utils.git

Code Formatting

Black automatically formats Python code. Add it as a development dependency and run it:

poetry add --dev black=19.3b0

poetry run black .

Type Correctness

Enable static type checking with mypy. Install and run it via Poetry:

poetry add --dev mypy

poetry run mypy .

Configure a mypy.ini file to fine‑tune warnings.

Automate the Automation

Pre‑commit runs checks before code is pushed. Install it in the virtual environment:

pyenv activate tools

pip install pre-commit

pyenv deactivate

pre-commit --version

Create a .pre-commit-config.yaml file (example excerpt):

repos:

-   repo: https://github.com/ambv/black

rev: 19.3b0

hooks:

-   id: black

-   repo: https://github.com/pre-commit/mirrors-mypy

rev: v0.740

hooks:

-   id: mypy

Install the hooks with: pre-commit install Run them on all files initially: pre-commit run --all-files With these tools combined, code formatting, type checking, and dependency management become automated, reducing manual effort and preventing errors.

In summary, using pyenv, Poetry, Black, mypy, and pre‑commit provides a streamlined, reproducible Python development workflow that lets developers focus on core logic rather than environment quirks.