Python Package and PIP

• Python’s power comes from its modular ecosystem. Instead of rewriting functionality, you can use packages collections of reusable modules and install additional external libraries using PIP, Python’s package manager.

What is PIP?¶

• PIP stands for "Pip Installs Packages". It is the official package manager for Python, allowing you to:

  • Install packages (libraries/modules) from the Python Package Index (PyPI).
  • Manage dependencies required for your Python projects.
  • Uninstall or upgrade packages when needed.

What is a Python Package?¶

• A Python package is a directory that contains multiple modules and includes an optional __init__.py file. In most cases:

  • A module is a single .py file (Python script).
  • A package is a collection of modules bundled for reuse.

• These packages can be installed via PIP and imported into your project to extend its capabilities.

Basic structure

my_package/
    __init__.py
    module_a.py
    module_b.py

Understanding Modules vs Packages vs Libraries¶

Checking if PIP is Installed¶

• PIP is included by default in Python versions 3.4 and above. To verify whether PIP is already installed on your system:

pip --version

• If you see a version number, it means PIP is installed.

Installing PIP (If Not Already Installed)¶

• If running pip --version throws an error, PIP might not be installed. To install it:

• Visit the official PIP installation page: https://pypi.org/project/pip/
• Alternatively, if using Python from python.org, PIP comes bundled with Python 3.4 and above.

Installing a Python Package using PIP¶

• To install a package, use the pip install <package-name> command.

pip install numpy

Using an Installed Package in Python¶

• Once a package is installed using PIP, it can be imported and used in your project to add powerful features.

Example: Using numpy for Numerical Computation¶

Searching for Packages on PyPI¶

• When you need a new feature or tool in your project, PyPI is the primary place to discover reliable, community-maintained packages.
• You can search directly from the website, or use command-line tools to locate relevant packages.

Searching Directly on the PyPI Website¶

• You can explore thousands of available packages on: https://pypi.org

Searching from the Command Line Using pip¶

• pip also provides a basic search feature:

pip search "machine learning"

• This command queries PyPI and returns a list of packages whose metadata matches the given phrase.

• Note: Some systems disable pip search due to API changes, but many environments still support it.

Uninstalling a Package¶

• If you no longer need a package, use the uninstall command:

• Press y to confirm and complete the uninstallation.

Show information about package¶

• The pip show command displays detailed information about a specific installed Python package

pip show <package_name>

Example:

pip show numpy

Listing All Installed Packages¶

• To see all installed Python packages in your environment:

pip list

Output¶

Package                               Version
------------------------------------- -------------------
absl-py                               1.4.0
accelerate                            1.8.1
aiofiles                              24.1.0
aiohappyeyeballs                      2.6.1
aiohttp                               3.11.15
.............................................
.............................................

Upgrading an Existing Package¶

• To upgrade a package to the latest version:

pip install --upgrade pandas

• You can also upgrade pip itself:

pip install --upgrade pip

Saving and Reproducing Environments¶

• For sharing or reproducing an environment:

Save installed packages to a file:¶

pip freeze > requirements.txt

Reinstall from the file on another machine:¶

pip install -r requirements.txt

pip help¶

• To see a list of available commands and options:

pip help

• This shows general help information, including the most commonly used commands.

Summary of PIP Commands¶