PY THON
CR ASH COURSE
A H A N D S - O N , P R O J E C T - B A S E D
I N T R O D U C T I O N T O P R O G R A M M I N G
ERIC MAT THES
,Python Crash Course
,
, Python
Crash Course
A Hands-On, Project-Based
Introduction to Programming
b y E r ic M a t t h e s
San Francisco
,Python Crash Course. Copyright © 2016 by Eric Matthes.
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
19 18 17 16 15 1 2 3 4 5 6 7 8 9
ISBN-10: 1-59327-603-6
ISBN-13: 978-1-59327-603-4
Publisher: William Pollock
Production Editor: Riley Hoffman
Cover Illustration: Josh Ellingson
Interior Design: Octopod Studios
Developmental Editors: William Pollock, Liz Chadwick, and Leslie Shen
Technical Reviewer: Kenneth Love
Copyeditor: Anne Marie Walker
Compositor: Riley Hoffman
Proofreader: James Fraleigh
For information on distribution, translations, or bulk sales, please contact No Starch Press, Inc. directly:
No Starch Press, Inc.
245 8th Street, San Francisco, CA 94103
phone: 415.863.9900;
www.nostarch.com
Library of Congress Cataloging-in-Publication Data
Matthes, Eric, 1972-
Python crash course : a hands-on, project-based introduction to programming / by Eric Matthes.
pages cm
Includes index.
Summary: "A project-based introduction to programming in Python, with exercises. Covers general
programming concepts, Python fundamentals, and problem solving. Includes three projects - how to
create a simple video game, use data visualization techniques to make graphs and charts, and build
an interactive web application"-- Provided by publisher.
ISBN 978-1-59327-603-4 -- ISBN 1-59327-603-6
1. Python (Computer program language) I. Title.
QA76.73.P98M38 2015
005.13'3--dc23
2015018135
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.
,About the Author
Eric Matthes is a high school science and math teacher living in Alaska,
where he teaches an introductory Python course. He has been writing
programs since he was five years old. Eric currently focuses on writing soft-
ware that addresses inefficiencies in education and brings the benefits of
open source software to the field of education. In his spare time he enjoys
climbing mountains and spending time with his family.
About the Technical Reviewer
Kenneth Love has been a Python programmer and teacher for many years.
He has given talks and tutorials at conferences, done professional train-
ings, been a Python and Django freelancer, and now teaches for an online
education company. Kenneth is also the co-creator of the django-braces
package, which provides several handy mixins for Django’s class-based
views. You can keep up with him on Twitter at @kennethlove.
,
, For my father, who always made time to
answer my questions about programming,
and for Ever, who is just beginning to ask me
his questions
,
, Brief Contents
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxvii
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxix
Part I: Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Chapter 1: Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Chapter 2: Variables and Simple Data Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Chapter 3: Introducing Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Chapter 4: Working with Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Chapter 5: if Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Chapter 6: Dictionaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Chapter 7: User Input and while Loops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Chapter 8: Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Chapter 9: Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
Chapter 10: Files and Exceptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
Chapter 11: Testing Your Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
Part II: Projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
Project 1: Alien Invasion
Chapter 12: A Ship That Fires Bullets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
Chapter 13: Aliens! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
Chapter 14: Scoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
CR ASH COURSE
A H A N D S - O N , P R O J E C T - B A S E D
I N T R O D U C T I O N T O P R O G R A M M I N G
ERIC MAT THES
,Python Crash Course
,
, Python
Crash Course
A Hands-On, Project-Based
Introduction to Programming
b y E r ic M a t t h e s
San Francisco
,Python Crash Course. Copyright © 2016 by Eric Matthes.
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
19 18 17 16 15 1 2 3 4 5 6 7 8 9
ISBN-10: 1-59327-603-6
ISBN-13: 978-1-59327-603-4
Publisher: William Pollock
Production Editor: Riley Hoffman
Cover Illustration: Josh Ellingson
Interior Design: Octopod Studios
Developmental Editors: William Pollock, Liz Chadwick, and Leslie Shen
Technical Reviewer: Kenneth Love
Copyeditor: Anne Marie Walker
Compositor: Riley Hoffman
Proofreader: James Fraleigh
For information on distribution, translations, or bulk sales, please contact No Starch Press, Inc. directly:
No Starch Press, Inc.
245 8th Street, San Francisco, CA 94103
phone: 415.863.9900;
www.nostarch.com
Library of Congress Cataloging-in-Publication Data
Matthes, Eric, 1972-
Python crash course : a hands-on, project-based introduction to programming / by Eric Matthes.
pages cm
Includes index.
Summary: "A project-based introduction to programming in Python, with exercises. Covers general
programming concepts, Python fundamentals, and problem solving. Includes three projects - how to
create a simple video game, use data visualization techniques to make graphs and charts, and build
an interactive web application"-- Provided by publisher.
ISBN 978-1-59327-603-4 -- ISBN 1-59327-603-6
1. Python (Computer program language) I. Title.
QA76.73.P98M38 2015
005.13'3--dc23
2015018135
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.
,About the Author
Eric Matthes is a high school science and math teacher living in Alaska,
where he teaches an introductory Python course. He has been writing
programs since he was five years old. Eric currently focuses on writing soft-
ware that addresses inefficiencies in education and brings the benefits of
open source software to the field of education. In his spare time he enjoys
climbing mountains and spending time with his family.
About the Technical Reviewer
Kenneth Love has been a Python programmer and teacher for many years.
He has given talks and tutorials at conferences, done professional train-
ings, been a Python and Django freelancer, and now teaches for an online
education company. Kenneth is also the co-creator of the django-braces
package, which provides several handy mixins for Django’s class-based
views. You can keep up with him on Twitter at @kennethlove.
,
, For my father, who always made time to
answer my questions about programming,
and for Ever, who is just beginning to ask me
his questions
,
, Brief Contents
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxvii
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxix
Part I: Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Chapter 1: Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Chapter 2: Variables and Simple Data Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Chapter 3: Introducing Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Chapter 4: Working with Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Chapter 5: if Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Chapter 6: Dictionaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Chapter 7: User Input and while Loops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Chapter 8: Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Chapter 9: Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
Chapter 10: Files and Exceptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
Chapter 11: Testing Your Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
Part II: Projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
Project 1: Alien Invasion
Chapter 12: A Ship That Fires Bullets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
Chapter 13: Aliens! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
Chapter 14: Scoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
