Python Virtual Environments

Why Virtual Environments?

Each Python project may need different package versions. Virtual environments isolate dependencies per project.

Setup and Usage

Create a virtual environment

python -m venv .venv

Activate

# Linux/macOS
source .venv/bin/activate

# Windows
.venv\Scripts\activate

Install packages

pip install requests flask
pip freeze > requirements.txt

Install from requirements.txt

pip install -r requirements.txt

Directory Structure

my-project/
├── .venv/              # Virtual environment (gitignore)
├── src/
│   └── main.py
├── requirements.txt    # Dependencies
└── .gitignore

Tips

• Always add .venv/ to .gitignore
• Use requirements.txt to share dependencies
• Consider uv or poetry for advanced dependency management