Python pip Package Manager

What Is pip in Python?

pip is a tool that comes with Python. It connects to the Python Package Index (PyPI) and lets us install packages from there.

PyPI is a huge repository of Python packages. There are hundreds of thousands of packages for almost anything you can think of.

How to Check if pip Is Installed

Most Python installations come with pip. We can check by running:

pip --version

pip 23.0.1 from /usr/lib/python3/dist-packages/pip (python 3.10)

If we see a version number, pip is installed.

How to Install a Package with pip

To install a package, we use pip install.

pip install requests

That installs the requests package. We can then import it in our Python code.

import requests

response = requests.get("https://api.github.com")
print(response.status_code)

200

That is how we install and use a package.

How to Install a Specific Version with pip

Sometimes we need a specific version of a package.

pip install requests==2.28.0

That installs version 2.28.0 of requests.

We can also install a minimum version.

pip install "requests>=2.28.0"

That installs version 2.28.0 or newer.

How to Upgrade a Package with pip

To upgrade a package to the latest version:

pip install --upgrade requests

Or shorter:

pip install -U requests

That updates the package to the newest version.

How to Uninstall a Package with pip

To remove a package:

pip uninstall requests

pip will ask for confirmation. Type y and press Enter.

How to List Installed Packages with pip

To see all installed packages:

pip list

Output (may vary):

Package    Version
---------- -------
pip        23.0.1
requests   2.28.0
numpy      1.24.0

That shows all packages and their versions.

How to Save and Install from requirements.txt

We can save the list of installed packages to a file.

pip freeze > requirements.txt

That creates a file with all packages and their exact versions.

To install from that file:

pip install -r requirements.txt

That installs all the packages listed. This is very useful for sharing projects.

How to Search for Packages with pip

pip does not have a built-in search command anymore. But we can search on PyPI’s website: pypi.org.

We can also use pip index versions to see available versions of a package.

pip index versions requests

That lists all available versions.

A Real-Life Example – Setting Up a Project with pip

Let us create a new project and install some packages.

mkdir myproject
cd myproject
python -m venv venv

Activate the environment.

On Windows:

venv\Scripts\activate

On Mac or Linux:

source venv/bin/activate

Install packages.

pip install requests flask

Save requirements.

pip freeze > requirements.txt

Now the project is set up. Anyone can install the same packages using:

pip install -r requirements.txt

That is a standard workflow.

Common Mistakes with pip in Python

pip3 install requests

pip install requests

pip list | grep requests