pip & Packages in Python

Learn how to install, manage and use external Python packages with pip.

What is pip?

pip is the standard package installer used to install Python packages from the Python Package Index and other configured package sources.

A package contains reusable Python code developed for a particular purpose.

What is a Python Package?

A Python package is reusable code that can be added to a project to provide additional functionality.

For example, developers can use external packages for web development, data analysis, machine learning, automation and many other tasks.

pip & Packages Diagram

The basic flow of installing and using a package can be understood like this:

Check Whether pip is Installed

We can check whether pip is available by using the following command in the terminal.

pip --version

Another commonly used form is:

python -m pip --version

The command displays the installed pip version.

Installing a Package

To install a package, use:

pip install package_name

For example:

pip install requests

This tells pip to install the requests package.

Example: Installing requests

First install the package:

pip install requests

Then use it in Python:

import requests

response = requests.get("https://example.com")

print(response.status_code)

The package provides functionality that is not part of the basic Python syntax.

Upgrade a Package

We can upgrade an installed package using:

pip install --upgrade package_name

Example:

pip install --upgrade requests

This asks pip to update the package to a newer available version.

Uninstall a Package

To remove an installed package:

pip uninstall package_name

Example:

pip uninstall requests

pip will ask for confirmation before removing the package.

View Installed Packages

We can display packages installed in the current Python environment using:

pip list

This displays package names and their installed versions.

View Package Details

To see information about a particular package:

pip show requests

This can display information such as the package version and installation location.

Using pip freeze

The following command displays installed packages in a format that can be saved as a requirements file.

pip freeze

Example output:

requests==2.x.x
urllib3==2.x.x
certifi==202x.x.x

The exact versions depend on the environment.

requirements.txt

A requirements.txt file is commonly used to list the Python packages required by a project.

Example:

requests==2.x.x
flask==3.x.x

Other developers can install the listed dependencies using:

pip install -r requirements.txt

This is useful when sharing or deploying a Python project.

Upgrade pip

pip itself can be upgraded with:

python -m pip install --upgrade pip

Using python -m pip is a common way to make sure pip is associated with the intended Python interpreter.

Common pip Commands

Built-in Modules vs External Packages

Package Management Flow

Common Mistakes

• Installing a package in a different Python environment than the one used by the project.
• Using an incorrect package name.
• Forgetting to install a required dependency.
• Not maintaining project dependencies properly.
• Confusing a Python module with an externally installed package.

Practical Exercise

Try these commands in your terminal:

pip --version

pip install requests

pip show requests

pip list

pip freeze

Then create a Python file and import the installed package.

import requests

print("Requests package is ready to use.")