Python Virtual Environments: Why Every Project Needs One

Why venv Matters

Different projects need different library versions. Installing everything globally eventually breaks something. A virtual environment gives each project its own isolated packages.

Creating One

python -m venv .venv

Activating

# macOS / Linux
source .venv/bin/activate

# Windows PowerShell
.venv\Scripts\Activate.ps1

Installing Packages

pip install requests numpy
pip freeze > requirements.txt

Deactivating

deactivate

Best Practices

• Always add .venv/ to .gitignore.
• Commit requirements.txt, not the venv itself.
• One venv per project.