Daniel Zingaro - Learn to Code by Solving Problems: A Python Programming Primer

A Python Programming Primer

by Daniel Zingaro

San Francisco

LEARN TO CODE BY SOLVING PROBLEMS. Copyright 2021 by Daniel Zingaro.

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.

ISBN-13: 978-1-7185-0132-4 (print)

ISBN-13: 978-1-7185-0133-1 (ebook)

Publisher: Bill Pollock

Executive Editor: Barbara Yien

Production Manager: Rachel Monaghan

Production Editor: Kassie Andreadis

Developmental Editor: Alex Freed

Interior and Cover Design: Octopod Studios

Cover Illustrator: Rob Gale

Technical Reviewer: Luke Sawczak

Copyeditor: Kim Wimpsett

Proofreader: Emelie Battaglia

Indexer: Sanjiv Kumar Sinha

For information on book distributors or translations, please contact No Starch Press, Inc. directly:

No Starch Press, Inc.

245 8th Street, San Francisco, CA 94103

phone: 1.415.863.9900;

www.nostarch.com

Library of Congress Cataloging-in-Publication Data

Names: Zingaro, Daniel, author.
Title: Learn to code by solving problems : a Python programming primer / by
Daniel Zingaro.
Description: San Francisco, CA : No Starch Press, [2021] | Includes index.
Identifiers: LCCN 2021011082 (print) | LCCN 2021011083 (ebook) | ISBN
9781718501324 (print) | ISBN 9781718501331 (ebook)
Subjects: LCSH: Python (Computer program language) | Computer programming.
Classification: LCC QA76.73.P98 Z55 2021 (print) | LCC QA76.73.P98
(ebook) | DDC 005.13/3--dc23
LC record available at https://lccn.loc.gov/2021011082
LC ebook record available at https://lccn.loc.gov/2021011083

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 author 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 Dad, for the computer code

and

To Mom, for the teacher code

Dr. Daniel Zingaro is an associate teaching professor of computer science and award-winning teacher at the University of Toronto. His main area of research is computer science education, where he studies how students learn (and sometimes dont learn) computer science material. He is the author of Algorithmic Thinking (No Starch Press, 2021), a book that helps learners understand and use algorithms and data structures.

Luke Sawczak is a frequent freelance editor and hobby programmer; his favorite projects include a prose-to-poetry converter, a visual aid for cutting the right number of slices of cake, and a version of Boggle that uses numbers made for math tutors. He currently teaches French and English on the outskirts of Toronto. He also writes poetry and composes for the piano, which he would do for a living if he could. He can be found online at https://sawczak.com/.

For real? I got to work with the No Starch Press people again? Barbara Yien brought me aboard. Bill Pollock and Barbara trusted me with the pedagogical approach of the book. Alex Freed, my developmental editor, was careful, kind, and timely. I thank all those involved in the production of the book, including my copyeditor Kim Wimpsett, production editor Kassie Andreadis, and cover designer Rob Gale. Im very lucky.

I thank the University of Toronto for offering me the time and space to write. I thank Luke Sawczak, my technical reviewer, for his careful review of the manuscript.

I thank everyone who contributed to the problems that I used in this book and to competitive programming in general. I thank the DMOJ administrators for their support of my work.

I thank my parents for handling everythingeverything. All they asked me to do was learn.

I thank Doyali, my partner, for giving more of our time to a book and for modeling the care it takes to write.

Finally, I thank all of you for reading this book and wanting to learn.

We use computers to accomplish tasks and to solve problems. For example, perhaps youve used a word processor to write an essay or letter. Perhaps youve used a spreadsheet program to organize your finances. Perhaps youve used an image editor to touch up a picture. Its hard to imagine doing these things these days without a computer. We get a lot of mileage out of our word processors and spreadsheet programs and image editors.

Those programs are written as general-purpose tools to accomplish a wide variety of tasks. Ultimately, though, theyre programs written by others, not by us. What do we do when an off-the-shelf program doesnt quite do what we need?

In this book, our goal is to learn how to take control of our computer by going beyond what can be done by an end user using preexisting programs. Were going to write our own programs. We wont write a word processor or a spreadsheet or an image editor. Those are huge tasks that, fortunately, people have already done. Rather, were going to learn how to write small programs to solve problems that we otherwise wouldnt be able to solve. I want to help you learn to communicate instructions to a computer; these instructions will tell the computer how to carry out your plan for solving a problem.

To give instructions to a computer, we write code in a programming language. A programming language specifies the rules for the code we write and dictates what the computer does in response to that code.

Were going to learn to program in the Python programming language. Thats a concrete skill that youll take away from this book, one that you can put on your rsum. More than Python, though, youll learn the type of thinking required to solve problems using a computer. Programming languages come and go. The way that we solve problems does not. I hope that this book helps you on your way from end user to programmer and that you have fun exploring whats possible.

Supplementary resources for the book, including downloadable code and additional exercises, are available at https://nostarch.com/learn-code-solving-problems/.

This book is for anyone who wants to learn how to write computer programs to solve problems. I have three particular types of people in mind.