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.