Web and API Dev Essentials

Lesson Summary: Virtual Environments in Python

Introduction & Purpose

• Virtual environments are essential to run code in isolated environments, separate from the system’s default Python installations.

Creating and Managing Virtual Environments

• Installation: Use sudo dnf install python3-virtualenv -y to install the necessary tool.
• Creating: Create a virtual environment using python -m venv <directory_name>.
• Activating: Activate it with source <directory_name>/bin/activate.
• Deactivating: Deactivate it simply by typing deactivate.
• Removing: Completely remove it using rm -rf <directory_name>.

Role of Virtual Environments

• They allow using specific Python interpreters and packages without affecting the system-wide Python setup.

Package Management with pip

• Installing pip: sudo dnf install python3-pip.
• Version Check: Ensure the versions of Python and pip match using python --version and pip --version.
• Basic Commands:
  • pip install <package> to install.
  • pip uninstall <package> to uninstall.
  • pip list to show installed packages.
  • pip search <package> to search for packages.
  • pip install --upgrade <package> to upgrade a package.
• Use pip install --user to avoid permission errors or activate a virtual environment before installation.

Saving and Reusing Package Requirements

• Freeze Requirements: Use pip freeze > requirements.txt to create a requirements file.
• Install from Requirements: Use pip install -r requirements.txt to install all packages listed.

Helpful Tips

• Use pip --help to see all available commands and options.
• Be cautious with the rm -rf command as it permanently deletes the directory and its contents.

Conclusion

• The lesson addresses how to create, manage, and destroy virtual environments, save required packages, and manage packages using pip.
• Emphasizes the importance of version compatibility between Python and pip.
• Advises against using elevated privileges with pip unless absolutely necessary.

This article is incomplete and work is being done on this.