Python - PIP

PIP stands for Package Installer for Python.

It is a package management tool that allows us to install, uninstall, and manage third-party packages written in Python.

These packages are downloaded from the Python Package Index (PyPI), the official online repository of Python packages.

Python comes with a standard library, but many useful features are provided by third-party packages.

For example, to work with an Oracle database, we need the cx_Oracle package. To work with a MySQL database, we need mysql-connector.

Without PIP, installing these packages would require downloading files manually. PIP automates this process.

To check whether PIP is installed and which version is available, run the following command in the command prompt:

pip 24.0 from C:\Python\Lib\site-packages\pip (python 3.12)

To install a package, use the pip install command followed by the package name.

The command should be run from a normal command prompt, not from the Python console.

Collecting cx_Oracle
  Downloading cx_Oracle-8.3.0-cp312-cp36m-win32.whl (200kB)
Installing collected packages: cx-Oracle
Successfully installed cx-Oracle-8.3.0

PIP connects to PyPI, downloads the requested package, and installs it automatically.

The output shows the package being collected and downloaded, followed by a success message at the end.

To install a particular version of a package, use == followed by the version number.

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To remove an installed package, use the pip uninstall command.

Found existing installation: requests 2.31.0
Uninstalling requests-2.31.0:
  Successfully uninstalled requests-2.31.0

To see all packages installed in the current environment, use the pip list command.

Package    Version
---------- -------
pip        24.0
setuptools 65.5.0
requests   2.31.0
cx_Oracle  8.3.0

To get detailed information about an installed package, use the pip show command.

Name: requests
Version: 2.31.0
Summary: Python HTTP for Humans.
Home-page: https://requests.readthedocs.io
Location: C:\Python\Lib\site-packages
Requires: certifi, charset-normalizer, idna, urllib3

To upgrade an already installed package to its latest version, use the --upgrade option.

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To share the list of dependencies with other developers, we can generate a file that lists every installed package and its version.

certifi==2024.2.2
charset-normalizer==3.3.2
idna==3.6
requests==2.31.0
urllib3==2.2.1

The output of pip freeze is usually saved into a file named requirements.txt.

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Another developer can install all the same packages at once using the -r option.

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This is a very common workflow in real projects.

• After setting up a project, run pip freeze > requirements.txt to save the exact dependencies.
• Share the requirements.txt file with the team.
• Anyone can recreate the same environment by running pip install -r requirements.txt.

Command	Purpose
pip install package_name	Install a package
pip uninstall package_name	Remove a package
pip list	Show all installed packages
pip show package_name	Show information about a package
pip freeze	List packages with exact versions
pip install -r requirements.txt	Install all packages from a file