Virtual Environments

Package Management with Pip

Pip is the standard package manager for Python. It allows you to install, manage, and uninstall packages (libraries) easily.

Key Commands:

• Installation:

pip install <package_name>

• To install a specific version:

pip install <package_name>==<version>

• To install from a requirements file:

pip install -r requirements.txt

(Requirements Files)

• Uninstallation:

pip uninstall <package_name>

• Listing Installed Packages:

pip list
pip freeze  # Shows installed packages and their versions in requirements format.

• Updating Packages:

pip install --upgrade <package_name>
pip install --upgrade -r requirements.txt #Update all packages from requirements.txt

• Searching for Packages:

pip search <search_term>

Virtual Environments: It’s crucial to use virtual environments to isolate project dependencies. Pip integrates well with venv (or virtualenv).

python3 -m venv .venv  # Creates a virtual environment named '.venv'
source .venv/bin/activate  # Activates the environment (Linux/macOS)
.venv\Scripts\activate  # Activates the environment (Windows)
pip install <package_name> # Install packages within the virtual environment
deactivate # Deactivates the environment

(Virtual Environments)

Other Useful Options:

• --user: Installs packages only for the current user.
• -t <directory>: Specifies the installation directory.
• --index-url <url>: Specifies an alternative PyPI index URL.

Troubleshooting:

• Permission Errors: You might need administrator privileges (sudo on Linux/macOS) to install packages globally. Virtual environments are a better solution to avoid permission issues.
• Network Issues: Ensure you have a stable internet connection.
• Proxy Settings: If you’re behind a proxy, you’ll need to configure pip to use it. (see pip documentation)

Pip Configuration Package Conflicts