React is a JavaScript web application framework for building rich user interfaces that run in web browsers.
Generally before you start working with React you will want to learn how to build your Python backend with a web framework such as Django, Flask or Pyramid. Once you get comfortable with the web development basics with one of those frameworks as well as JavaScript then it will be much easier to tack on React to build your client-side user interfaces.
JavaScript fundamentals before learning React provides a gut check that you have the prerequisite knowledge to avoid getting impossibly stuck while trying to learn React.
The official React tutorial is one of the best ways to start using React because many other tutorials quickly fall out of date while this one tends to stick to the basics that are relevant to beginners.
9 things every React.js beginner should know is not a tutorial but instead the author gives some strong opinions for what beginners should know as they start learning React.
React Bootstrap (source code replaces the existing Bootstrap JavaScript with React components that do not rely on jQuery.
How to set up Django with React presents one developer's opinionated way of combining a Django-powered back end with React on the front end, including how to serve up static assets.
Django REST with React (Django 2.0 and a sprinkle of testing) combines a Django plus Django REST Framework (DRF) backend with React on the front end and shows how to stich it all together.
This Modern Django 4-part tutorial series is well-done, has freely available source code and includes:
Build a Simple CRUD App with Python, Flask, and React shows how to combine a Flask backend with React.
Learn React app is a Git repository with a code tutorial and instructions for how to follow along, as well as exercises to ensure you are tested as you go.
React interview questions is a good quiz to see what you know or still need to learn about the fundamentals of using React.
Under-the-hood-ReactJS examines the React codebase itself rather than teaching you how to use it.