The Book of Dash

187 Pages·2022·2.761 MB·English

by  Adam Schroeder, Christian Mayer, and Ann Marie Ward

CONTENTS IN DETAIL
TITLE PAGE
COPYRIGHT
DEDICATION
ABOUT THE AUTHORS
ACKNOWLEDGMENTS
INTRODUCTION
Why This Book
Why Plotly Dash
Who This Book Is For
What’s in the Book
Online Resources
PART I: CRASH COURSES
1
PYTHON REFRESHER
Lists
Adding Elements
Removing Elements
Reversing Lists
Sorting Lists
Indexing List Elements
Slicing
Dictionaries
List Comprehension
Object-Oriented Programming
Classes and Objects
Terminology
Decorator Functions and Annotations
Summary
2
PYCHARM TUTORIAL
Installing PyCharm
Creating a Project
Running a Dash App
Installing Dash Through PyCharm
Using Dash with GitHub
Summary
3
A CRASH COURSE IN PANDAS
Visual Overview Cheat Sheet
Installing pandas
Creating Objects in pandas
Series
DataFrames
Selecting Elements in DataFrames
Select by Column
Select by Index and Slice
Select by Label
Modifying an Existing DataFrame
Summary
Resources
PART II: BUILDING APPLICATIONS
4
FIRST DASH APP
Setting Up the Project
Importing the Libraries
Data Management
Layout and Styling
Styling: Embellishing Your App
Dash Components
HTML Components
Core Components
Dash Callbacks
Callback Decorator
Callback Function
Callback Diagram
Plotly Express Line Charts
Summary
5
GLOBAL DATA ANALYSIS: ADVANCED LAYOUTS AND GRAPHS
Setting Up the Project
Importing the Libraries
Data Management
Dash Bootstrap Styling
Dash Core Components
Dash Callbacks
Data Retrieval Callback
Figure Creation Callback
Callback Diagram
Callback Ordering
Plotly Express Choropleth Maps
Summary
6
INVESTMENT PORTFOLIO: BUILDING LARGER APPS
Asset Allocation
Download and Run the App
App Structure
Setting Up the Project
Importing the Libraries
Adding the Stylesheets
Data Management
Layout and Styling
Components
Tabs
Card Containers and Sliders
Input Containers
Tool Tips
Data Tables
Content Tables
Markdown Text
Pie Chart Using Plotly Graph Objects
Line Chart Using Plotly Graph Objects
Dash Callbacks
Interactive Figures
Callbacks Using State
Circular Callbacks and Synchronizing Components
Callbacks with Multiple Inputs and Multiple Outputs
Summary
7
EXPLORING MACHINE LEARNING
Dashboard Apps to Make Machine Learning Models More Intuitive
Classification: A Short Guide
Support Vector Machines
The SVM Explorer App
Python Libraries
Data Management
Layout and Styling
Layout
Styling
Reusable Components
Defining a Card
Defining a Formatted Slider
Defining a Named Slider
Defining a Named Dropdown
Using a Dash Graph
Creating a Plotly Contour Plot
Using Dash Loading
Dash Callbacks
Summary
Resources
8
TIPS AND TRICKS
Dash Enterprise App Gallery
Enhancing Your Learning with the Plotly Forum
App Theme Explorer
Debugging a Dash App
dash-labs
Formatting Your Code with Black
Follow-up Resources
APPENDIX: PYTHON BASICS
INDEX
THE BOOK OF DASH
Build Dashboards with Python and Plotly
by Adam Schroeder, Christian Mayer, and Ann Marie
Ward
THE BOOK OF DASH. Copyright © 2022 by Adam Schroeder, Christian Mayer, and Ann Marie Ward.
All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means, electronic or mechanical,
including photocopying, recording, or by any information storage or retrieval system, without the prior written permission of the copyright
owner and the publisher.
First printing
26 25 24 23 22    1 2 3 4 5
ISBN-13: 978-1-7185-0222-2 (print)
ISBN-13: 978-1-7185-0223-9 (ebook)
Publisher: William Pollock
Managing Editor: Jill Franklin
Production Manager: Rachel Monaghan
Production Editor: Jennifer Kepler
Developmental Editor: Liz Chadwick
Cover Illustrator: Gina Redman
Interior Design: Octopod Studios
Technical Reviewer: Tom Begley
Copyeditor: Audrey Doyle
Production Services: Westchester Publishing Services
Proofreader: Rachel Head
Indexer: BIM Creatives, LLC
For information on distribution, bulk sales, corporate sales, or translations, please contact No Starch Press, Inc. directly at
[email protected] or:
No Starch Press, Inc. 245 8th Street, San Francisco, CA 94103 phone: [phone] www.nostarch.com
Library of Congress Control Number: 2022020454
No Starch Press and the No Starch Press logo are registered trademarks of No Starch Press, Inc. Other product and company names
mentioned herein may be the trademarks of their respective owners. Rather than use a trademark symbol with every occurrence of a
trademarked name, we are using the names only in an editorial fashion and to the benefit of the trademark owner, with no intention of
infringement of the trademark.
The information in this book is distributed on an “As Is” basis, without warranty. While every precaution has been taken in the preparation
of this work, neither the authors nor No Starch Press, Inc. shall have any liability to any person or entity with respect to any loss or damage
caused or alleged to be caused directly or indirectly by the information contained in it.
To Isabel, my beloved wife.
—Adam
About the Authors
Adam Schroeder has been teaching Plotly Dash for over two years on YouTube as @CharmingData.
His videos have over 60,000 views per month. Adam is passionate about helping people learn data
visualization. He has an MA in government and conflict resolution and works for Plotly.
Christian Mayer has a PhD in computer science and is the founder of the popular Python site
Finxter.com, an educational platform that helps more than 5 million people a year learn to code. He has
published a number of books, including the Coffee Break Python series, and is the author of Python
One-Liners (No Starch Press, 2020) and The Art of Clean Code (No Starch Press, 2022).
Ann Marie Ward is a Dash contributor and a moderator on the Dash community forum. Ann Marie
has a BA in economics and is a retired CEO. She discovered Dash when searching for a better way to
analyze financial data and was so amazed by what’s possible to create with Dash that she started to
learn Python, JavaScript, and R. Her contributions to Dash include improving documentation, fixing
bugs, and adding features.
About the Technical Reviewer
Tom Begley is a data scientist and the co-creator and maintainer of dash-bootstrap-components. He has
a PhD in mathematics and five years of experience working as a data scientist in industry. He
discovered Dash when looking for ways to build interactive data visualizations for his clients, and has
since become an active contributor to the Dash community and ecosystem.
ACKNOWLEDGMENTS
Putting together a programming book like this is a group effort that builds on the ideas and
contributions of many people.
First and foremost, we want to thank you, the reader, for spending your valuable time with us. Our
main goal is to make reading this book worth your while and, hopefully, get you as excited as we are
about creating your own dashboard applications.
We would also like to thank the Plotly Dash community members for making the Plotly forum a
thriving place. Over the years, we’ve learned a lot from the forum and honed our Dash skills thanks to
the curiosity and constant support of the community.
Our deep gratitude goes to the wonderful team at No Starch Press for making the book writing
process such a delightful experience. Special thanks to our outstanding editor, Liz Chadwick, for being
there for us throughout the project. Liz truly is a one-of-a-kind editor, and we’re very lucky to have had
her support! Jennifer Kepler, our production editor, pushed this book from rough draft to final
publication, which was not an easy endeavor—thanks a million, Jennifer! Our technical reviewer, Tom
Begley, helped us significantly improve this book by contributing his impressive technical programming
and Dash expertise. Moreover, we’re thankful to Bill Pollock, founder of No Starch Press, for believing
in our project and allowing us to contribute to his inspiring mission to educate more coders.
Lastly, we’re very grateful to our beloved partners for enduring the long night and weekend shifts
to work on this project.
And with that, let’s get started!
INTRODUCTION
Information is power, some say. Data is the new gold,
others proclaim. But raw information and data are often
meaningless without context. Data is a valuable asset
only when properly analyzed, interpreted, and understood. As a result,
new fields proliferate. Data scientist, data engineer, data analyst, business
intelligence consultant, and machine learning engineer are all increasingly
popular careers, and they all share a common role: interpreting data using
visual tools such as graphs and dashboards.
The goal of this book is to help you create beautiful dashboard apps so that you can visualize your
data with just a few lines of code. Whether you’re an aspiring professional, you work with data on a
regular basis, or you just love to play with numbers, this book will give you the tools and education to
harness the power of data.
Why This Book
The Plotly Dash framework makes it super easy for you to build your own dashboards. Dashboards are
web apps that allow you and your users to dynamically explore data using interactive widgets that
receive user input to explain output. For example, they might have sliders, text fields, buttons, and
dropdown menus to allow the user to choose what data to show in the resultant charts and graphs, like
the maps and bar charts you see in Figure 1. The interactivity of dashboard apps is what has made them
increasingly popular in recent years.