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44. Virtual Environments Revisited

1. Introduction​

We first saw virtual environments in Chapter 16.
Here, we’ll reinforce their importance in real-world projects.

2. Why Use Virtual Environments?​

  • Isolate dependencies for each project.
  • Prevent version conflicts.
  • Keep global Python clean.

3. Creating a Virtual Environment​

python3 -m venv venv

4. Activating the Environment​

  • Windows (cmd): venv\Scripts\activate
  • PowerShell: venv\Scripts\Activate.ps1
  • Linux/macOS: source venv/bin/activate

5. Installing Packages in Virtual Environments​

pip install requests

Packages stay isolated inside venv/lib/.

6. Freezing Dependencies​

pip freeze > requirements.txt

Recreate environment:

pip install -r requirements.txt

7. Deactivating and Removing​

deactivate
rm -rf venv

8. Next Steps​

✅ You now understand how to use virtual environments effectively.
In the next chapter, we’ll revisit installing packages with pip.