Python Virtual Environments

A virtual environment (venv) creates an isolated space for your project’s packages. Without venv: - packages get installed globally - projects can break each other due to version conflicts With venv: - each project has its own dependencies - your computer stays clean ## Create and activate a venv (step by step) Create: ```bash python -m venv .venv ``` Activate: ### Windows (PowerShell) ```bash .venv\Scripts\Activate.ps1 ``` ### macOS/Linux ```bash source .venv/bin/activate ``` ## Install packages inside the venv ```bash pip install requests ``` ## Save dependencies (so others can set up the project) ```bash pip freeze > requirements.txt ``` Install from file: ```bash pip install -r requirements.txt ``` ## Best practice: .gitignore Do not commit your environment folder: ``` .venv/ ``` ## Graph: isolation concept ```mermaid flowchart LR A[Project A] --> B[(.venv A)] C[Project B] --> D[(.venv B)] B --> E[Packages A] D --> F[Packages B] ``` In the next lesson, you will learn *args and **kwargs, which helps you build flexible, reusable functions in professional code.