Index

Please note that index links to approximate location of each term.

Symbols

+ (addition), 26

+= (addition in place), 122

* (arbitrary arguments), 146

** (arbitrary keyword arguments), 148

{} (braces)

dictionaries, 92

sets, 104

@ (decorator), 221, 424

/ (division), 26

== (equality), 72, 74

** (exponent), 26

> (greater than), 75

>= (greater than or equal to), 75

# (hash mark), for comments, 29

!= (inequality), 74

< (less than), 75

<= (less than or equal to), 75

[] (list), 34

% (modulo), 116

+= (multiline strings), 115

* (multiplication), 26

\n (newline), 22

>>> (Python prompt), 4

- (subtraction), 26

\t (tab), 22

_ (underscore)

in file and folder names, 10

in numbers, 28

in variable names, 17

aliases, 151–152, 178–179

alice.py, 195–197

Alien Invasion. See also Pygame

aliens, 256–274

building fleet, 259–262

checking edges, 265

collisions, with bullets, 267

collisions, with ship, 270–273

controlling fleet direction, 264–266

creating an alien, 256–258

dropping fleet, 265–266

reaching bottom of screen, 273–274

rebuilding fleet, 268–269

bullets, 247–253, 266–270

collisions, with aliens, 267

deleting old, 250–251

firing, 249–250

larger, 268

limiting number of, 251–252

settings, 247

speeding up, 269

classes

Alien, 257

AlienInvasion, 229

Bullet, 247–248

Button, 278–279

GameStats, 271

Scoreboard, 286–287

Settings, 232

Ship, 234–235

ending the game, 274–275

initializing dynamic settings, 283–285

levels

modifying speed settings, 283–285

resetting the speed, 285

displaying, 294–296

moving fleet, 263–266

planning, 228

Play button, 278–283

Button class, 278–279

deactivating, 282

drawing, 279–280

hiding mouse cursor, 282–283

resetting game, 281–282

starting game, 281

reviewing the project, 256

scoring, 286–298

all hits, 290

high score, 292–294

increasing point values, 290–291

level, 294–296

number of ships, 296–299

resetting, 289–290

rounding and formatting, 291–292

score attribute, 286

updating, 289

settings, storing, 232–233

ship, 233–244

adjusting speed, 242–243

continuous movement, 239–242

finding an image, 233–234

limiting range, 243–244

amusement_park.py, 80–82

and keyword, 75

antialiasing, 279

API. See application programming interface

apostrophe.py, 24–25

append() method, 37–38

application programming interface (API), 355

API call, 355–357

GitHub API, 368

Hacker News API, 368–371

processing an API response, 357–362

rate limits, 362

requesting data, 356–357

visualizing results, 362–368

arguments, 131. See also under functions

as keyword, 151–152

assertions, 213, 217–218

attributes, 159. See also under classes

banned_users.py, 76–77

bicycles.py, 34–35

Boolean values, 77

Bootstrap, 433. See also unxder Django

braces ({})

dictionaries, 92

sets, 104

break statement, 121

built-in functions, 467

calls (functions), 130, 132–135

car.py, 162–178

cars.py, 43–45, 72

cities.py, 121

classes

attributes, 159

accessing, 160

default values, 163–164

modifying, 164–166

creating, 158–161

importing, 173–179

multiple classes, 175–176

single classes, 174–175

inheritance, 167–172

attributes and methods, 169

child classes, 167–170

composition, 170

__init__() method, 167–169

instances as attributes, 170–172

overriding methods, 170

parent classes, 170

subclasses, 168

super() function, 168

superclasses, 168

instances, 157

methods, 159

calling, 160

chaining, 185

__init()__ method, 159

modeling real-world objects, 172–173

multiple instances, 161

naming conventions, 158

objects, 157

style guidelines, 181

comma-separated value files. See CSV files

comment.py, 29

comments, 29–30

conditional tests, 72–77. See also if statements

confirmed_users.py, 124–125

constants, 28

continue statement, 122

counting.py, 117–118, 122–123

CSV files, 330–341

csv.reader() function, 330–333

error checking, 338–341

file headers, 330–332

data analysis, 301

databases. See under Django

data visualization, 301. See also Matplotlib; Plotly

datetime module, 333–335

death_valley_highs_lows.py, 339–341

decorators, 221–223, 423–425

default values

class attributes, 163–164

function parameters, 134–135

definition (functions), 130

def keyword, 130

del statement

with dictionaries, 96

with lists, 38–40

dice_visual_d6d10.py, 326–327

dice_visual.py, 324–326

dictionaries

defining, 92

empty, 94

formatting larger, 96–97

KeyError, 98

key-value pairs, 92

adding, 93–94

removing, 96

looping through

keys, 101–102

keys in order, 102–103

key-value pairs, 99–101

values, 103–104

methods

get(), 97–98

items(), 99–101

keys(), 101–103

values(), 103–104

nesting

dictionaries in dictionaries, 110–111

dictionaries in lists, 105–108

lists in dictionaries, 108–109

ordering in, 94, 102–103

sorting a list of, 370

values

accessing, 92–93, 97–98

modifying, 94–96

die.py, 320

die_visual.py, 320–321

dimensions.py, 66–67

div (HTML), 437

division_calculator.py, 192–195

Django. See also Git; Learning Log project

accounts app, 415–423

creating app, 415–416

logging out, 419–420

registration page, 420–423

admin site, 381–386

associating data with a user, 425–430

Bootstrap, 434–445

card, 443

collapsible navigation, 437

container, 440

django-boostrap5 app, 434

documentation, 444

HTML headers, 435–436

jumbotron, 440–441

list groups, 443

navigation bar, 436–439

styling forms, 441–442

commands

createsuperuser, 382

flush, 427

makemigrations, 381, 385, 426

migrate, 377

runserver, 377–378, 383, 392

shell, 386

startapp, 379, 415

startproject, 376

creating new projects, 376

databases

cascading delete, 384

creating, 376

foreign keys, 384, 425

many-to-one relationships, 384

migrating, 377, 381, 385, 426

non-nullable field, 427

Postgres, 447

queries, 398, 428

querysets, 386–387, 395, 398, 426–428

resetting, 427

SQLite, 377

deployment, 445–461, 493–501

committing the project, 453

configuration files, 447–450

creating Platform.sh project, 453–455

creating superuser, 456–457

custom error pages, 459–460

deleting projects, 461

free trial limits, 446

gunicorn, 447

ignoring files, 452–453

installing Platform.sh CLI, 446, 497–500

installing platformshconfig, 446

other deployment approaches, 500

Platform.sh, 445

Postgres database, 447, 450–451

psycopg2, 447

pushing a project, 455

pushing changes, 458, 460

requirements.txt, 446

securing project, 457–460

settings, 451

SSH sessions, 456–457

troubleshooting, 494–501

using Git, 451

viewing project, 456

development server, 377–378, 383, 392

documentation

model fields, 380

queries, 388

templates, 400

forms, 404–423, 429–430

csrf_token, 407

GET and POST requests, 406

ModelForm, 404, 408

processing forms, 405–406, 409–410, 412–413, 421–422, 429–430

save() method, 405–406, 409–410, 430

templates, 407, 410–411, 413, 417, 419, 422

validation, 404–406

widgets, 408

HTML

anchor tag (<a>), 393

<body> element, 437

comments, 437

<div> elements, 437

<main> element, 440

margins, 440

padding, 440

<p> elements, 391

<span> elements, 438

HTTP 404 error, 428–429, 459–460

INSTALLED_APPS, 380

installing, 375–376

localhost, 378

logging out, 419–420

@login_required decorator, 423–424

mapping URLs, 388–390, 397–398

migrating the database, 426–427

models, 379

activating, 380–381

defining, 379, 384

foreign keys, 384, 425

registering with admin, 382–383, 385–386

__str__() method, 380, 384

projects (vs. apps), 379

redirect() function, 405–406

release cycle, 376

restricting access to data, 427–430

settings

ALLOWED_HOSTS, 451

DEBUG, 457–458

INSTALLED_APPS, 380–381, 415–416, 434

LOGIN_REDIRECT_URL, 417–418

LOGIN_URL, 424

LOGOUT_REDIRECT_URL, 420

SECRET_KEY, 451

shell, 386–387, 426–427

starting an app, 379

styling. See Django: Bootstrap

superusers, 382, 456–457

templates

block tags, 393

child template, 393–394

context dictionary, 395

filters, 399

forms in, 407

indentation in, 393

inheritance, 392–394

linebreaks, 399

links in, 392–393, 399

loops in, 395–397

parent template, 392–393

template tags, 393

timestamps in, 398–399

user object, 418

writing, 390–392

URLs. See Django: mapping URLs

UserCreationForm, 421–422

user ID values, 426

versions, 376

view functions, 388, 390

virtual environments, 374–375

docstrings, 130, 153, 181

dog.py, 158–162

dot notation, 150, 160

earthquakes. See mapping earthquakes

electric_car.py, 167–173

module, 177–179

encoding argument, 195–196

enumerate() function, 331

eq_explore_data.py, 343–347

equality operator (==), 72, 74

eq_world_map.py, 347–352

even_numbers.py, 58

even_or_odd.py, 117

exceptions, 183, 192–199

deciding which errors to report, 199

else block, 194–195

failing silently, 198–199

FileNotFound error, 195–196

handling exceptions, 192–196

preventing crashes, 193–195

try-except blocks, 193

ZeroDivisionError, 192–195

exponents (**), 26

favorite_languages.py, 96–97, 100–104, 109

file_reader.py, 184–187

files

encoding argument, 195–196

FileNotFound error, 195–196

file paths, 186

absolute, 186

exists() method, 203–204

pathlib module, 184

Path objects, 184–186, 330

relative, 186

from strings, 198

on Windows, 186

read_text() method, 185, 195–196

splitlines() method, 186–187

write_text() method, 190–191

first_numbers.py, 57

fixtures, 221–223

flags, 120–121

floats, 26–28

foods.py, 63–64

for loops, 49–56, 99–104. See also dictionaries; lists

formatted_name.py, 137–139

f-strings

format specifiers, 291–292

using variables in, 20–21

full_name.py, 21

functions, 129–155

arguments

arbitrary, 146–149

default values, 134–135

errors, 136

keyword, 133–134

lists as, 142–145

optional, 138–139

positional, 131–133

body, 130

built-in, 467

calling functions, 130, 132–135

defining, 130

importing, 149–153

aliases, 151–152

entire modules, 150–151

specific functions, 151

modifying a list in a function, 142–145

modules, 149–153

parameters, 131

return values, 137–141

style guidelines, 153

GeoJSON files, 342–347, 350–351

GET requests, 406. See Django: forms

getting help

Discord, 480

official Python documentation, 479–480

online resources, xxxv, 478

r/learnpython, 480

rubber duck debugging, 478

searching online, 479

Slack, 481

Stack Overflow, 479

three main questions, 477–478

Git, 356, 451–453, 483–492. See also Django: deployment

abandoning changes, 488–489

adding files, 486

branches, 486

checking out previous commits, 489–491

commits, 486–488

configuring, 452, 484

deleting a repository, 491–492

.gitignore, 484

HEAD, 490

ignoring files, 484

initializing a repository, 485

installing, 484

log, 487

repositories, 356

status, 485–486

GitHub, 356

greeter.py, 114–115, 130–131

greet_users.py, 142

Hacker News API, 368–371

hash mark (#), for comments, 29

hello_git.py, 484–491

hello_world.py, 10–12, 15–19

hidden files, 448, 485

hn_article.py, 368–369

hn_submissions.py, 369–371

IDE (integrated development environment), 469–470

if statements

and keyword, 75

Boolean expressions, 77

checking for

equality (==), 72

inequality (!=), 74

item in list, 76

item not in list, 76

list not empty, 86–87

elif statement, 80–83

else statement, 79–80

if statements and lists, 85–88

ignoring case, 73–74

numerical comparisons, 74–76

or keyword, 76

simple, 78

style guidelines, 89

testing multiple conditions, 82–83

immutable, 65

import *, 152, 177

import this, 30–31

indentation errors, 53–56

index errors, 46–47

inheritance, 167–173. See also under classes

input() function, 114–116

numerical input, 115–116

writing prompts, 114–115

insert() method, 38

itemgetter() function, 370

items() method, 99–101

JSON files

GeoJSON files, 342–347, 350–351

JSON data format, 201

json.dumps() function, 201–204, 343–344, 368

json.loads() function, 201–204, 343–344

keys() method, 101–103

key-value pairs, 92. See also dictionaries

keyword arguments, 133–134

keywords, 466

language_survey.py, 219

Learning Log project, 373

files, 392

404.html, 459

500.html, 459

accounts/urls.py, 416, 420

accounts/views.py, 421–422

admin.py, 382–383

base.html, 392–393, 396, 418–419, 422, 435–440

edit_entry.html, 413

forms.py, 404, 408–409

.gitignore, 452–453

index.html, 390–394, 440–441

learning_logs/urls.py, 389–390, 394–395, 397–398, 405, 409, 412

learning_logs/views.py, 390, 395, 398, 405–406, 409–410, 412–413, 423–425, 428–430

ll_project/urls.py, 388–389, 416

login.html, 417, 441–442

models.py, 379–380, 384

new_entry.html, 410

new_topic.html, 407

.platform.app.yaml, 448–450

register.html, 422

requirements.txt, 446–447

routes.yaml, 450

services.yaml, 450

settings.py, 380–381, 415–418, 420, 424, 434, 451, 457–460

topic.html, 398–399, 443–444

topics.html, 395–396, 442–443

ongoing development, 460

pages, 391

edit entry, 412–414

home page, 388–394

new entry, 408–411

new topic, 404–408

registration, 420–423

topic, 397–400

topics, 394–397

writing a specification (spec), 374

len() function, 44–45

library, 184

Linux

Python

checking installed version, 8

setting up, 8–12, 465–466

terminals

running programs from, 12

starting Python session, 9

troubleshooting installation issues, 10

VS Code, installing, 9

lists, 33

as arguments, 142–145

comprehensions, 59–60

copying, 63–64

elements

accessing, 34

accessing last, 35

adding with append(), 37–38

adding with insert(), 38

identifying unique, 104

modifying, 36–37

removing with del, 38–39

removing with pop(), 39–40

removing with remove(), 40–41

empty, 37–38

enumerate() function, 331

errors

indentation, 53–56

index, 46

for loops, 49–56

nested, 108–109, 261–262

indexes, 34–35

negative index, 35

zero index, 34–35

len() function, 44–45

naming, 33–34

nesting

dictionaries in lists, 105–108

lists in dictionaries, 108–109

numerical lists, 56–60

max() function, 59

min() function, 59

range() function, 58–59

sum() function, 59

removing all occurrences of a value, 125

slices, 61–62

sorting

reverse() method, 44

sorted() function, 43–44

sort() method, 43

square brackets, 34

logical errors, 54

lstrip() method, 22–23

macOS

.DS_Store files, ignoring, 453

Homebrew package manager, 499

Python

checking installed version, 7

setting up, 7–12, 464–465

terminals

running programs from, 12

starting Python session, 7

troubleshooting installation issues, 10

VS Code, installing, 8

magicians.py, 49–56

magic_number.py, 74

making_pizzas.py, 150–152

mapping earthquakes, 342–352. See also Plotly

downloading data, 343, 352

GeoJSON files, 342–347, 350–351

latitude-longitude ordering, 345

location data, 346–347

magnitudes, 346

world map, 347–348

Matplotlib

axes

set_aspect() method, 313–314

removing, 317

ax objects, 303

colormaps, 310–311

fig objects, 303

figsize argument, 318

formatting plots

alpha argument, 337–338

built-in styles, 306

custom colors, 310

labels, 303–304

line thickness, 303–304

plot size, 318

shading, 337–338

tick labels, 309–310

gallery, 302

installing, 302

plot() method, 303–306

pyplot module, 302–303

savefig() method, 311

saving plots, 311

scatter() method, 306–311

simple line graph, 302–306

subplots() function, 303

methods, 20

helper methods, 237

modules, 149–152, 173–179. See also classes: importing; functions: importing

modulo operator (%), 116–117

motorcycles.py, 36–41

mountain_poll.py, 125–126

mpl_squares.py, 302–306

my_car.py, 174–175

my_cars.py, 176–179

my_electric_car.py, 176

name errors, 17–18

name_function.py, 211–217

name.py, 20

names.py, 211–212

nesting. See dictionaries: nesting; lists: for loops

newline (\n), 21–22

next() function, 330–331

None, 98, 140

number_reader.py, 202

numbers, 26–28

arithmetic, 26

constants, 28

exponents, 26

floats, 26–27

formatting, 291–292

integers, 26

mixing integers and floats, 27–28

order of operations, 26

round() function, 291–292

underscores in, 28

number_writer.py, 201

object-oriented programming (OOP), 157. See also classes

or keyword, 76. See also if statements

pandas, 320

parameters, 131

parrot.py, 114, 118–121

pass statement, 198–199

paths. See files: file paths

PEP 8, 68–69

person.py, 139–140

pets.py, 125, 132–136

pip, 210–211

installing Django, 374–376

installing Matplotlib, 302

installing Plotly, 320

installing Pygame, 228

installing pytest, 211

installing Requests, 357

Linux, installing pip, 465–466

updating, 210

pi_string.py, 187–189

pizza.py, 146–148

Platform.sh. See Django: deployment

players.py, 61–62

Plotly, 302, 319. See also mapping earthquakes; rolling dice

chart types, 322

customizing plots, 323, 325–326, 364

documentation, 368

fig.show() method, 322

fig.write_html() method, 327

formatting plots

axis labels, 323

color scales, 349–350

hover text, 350–351, 365–366

links in charts, 366–367

marker colors, 349–350, 367

tick marks, 325–326

titles, 323

tooltips, 365–366

update_layout() method, 325–326, 364

update_traces() method, 367

gallery, 320

histograms, 322

installing, 320

plotly.express module, 322, 347, 368

px alias, 322

px.bar() function, 322–323, 363–367

saving figures, 327

scatter_geo() function, 347–352

pop() method, 39–40

positional arguments, 131–133. See also functions: arguments

POST requests, 406. See also Django: forms

printing_models.py, 143–145

Project Gutenberg, 196–197

prompts, 114–115

.py file extension, 15–16

Pygame. See also Alien Invasion

background colors, 231–232

clock.tick() method, 230–231

collisions, 266–267, 270–271, 289–290

creating an empty window, 229–230

cursor, hiding, 282–283

displaying text, 278–280

ending games, 274–275

event loops, 229–230

frame rates, 230–231

fullscreen mode, 245

groups

adding elements, 249–250

defining, 248–249

drawing all elements in, 249–250, 257–258

emptying, 268–269

looping through, 249–251

removing elements from, 250–251

updating all elements in, 248–249

images, 234–236

installing, 228

levels, 283–285

Play button, 278–283

print() calls in, 251

quitting, 244–245

rect objects, 234–235

creating from scratch, 247–248

get_rect() method, 234–235

positioning, 234–235, 238–243, 247–248, 256–262, 278, 286–298

size attribute, 261

responding to input, 230

events, 230

keypresses, 238–242

mouse clicks, 281–283

screen coordinates, 235

surfaces, 230

testing games, 268

pytest. See testing code

Python

>>> prompt, 4

built-in functions, 467

checking installed version, 466

installing

on Linux, 465–466

on macOS, 7–11, 464–465

on Windows, 5–6, 463–464

interpreter, 15–16

keywords, 466

Python Enhancement Proposal (PEP), 68

standard library, 179–180

terminal sessions, 4

on Linux, 9

on macOS, 7–8

on Windows, 6

versions, 4

why use Python, xxxvi

python_repos.py, 357–362

python_repos_visual.py, 362–367

quit values, 118

random_walk.py, 312–313

random walks, 312–318

choice() function, 313

coloring points, 315–316

fill_walk() method, 312–313

generating multiple walks, 314–315

plotting, 313–314

RandomWalk class, 312–313

starting and ending points, 316–317

range() function, 58–59

read_text() method, 185, 195–196

refactoring, 204–206, 237–238, 260, 269–270

remember_me.py, 202–206

removeprefix() method, 24

removesuffix() method, 25

Requests package, installing, 357

return values, 137–141

rollercoaster.py, 116

rolling dice, 319–327. See also Plotly

analyzing results, 321–322

Die class, 320

different-size dice, 326–327

randint() function, 320

rolling two dice, 324–326

rubber duck debugging, 478

rstrip() method, 22–23

rw_visual.py, 313–318

scatter_squares.py, 306–311

sets, 103–104

sitka_highs_lows.py, 336–338

sitka_highs.py, 330–336

sleep() function, 272

slices, 61–64

sorted() function, 43–44, 102–103

sort() method, 43

splitlines() method, 186–187

split() method, 196–197

SQLite database, 376–377

square_numbers.py, 58–59

squares.py, 59–60

Stack Overflow, 479

storing data, 201–204. See also JSON files

saving and reading data, 202–204

strings, 19–25

changing case, 20

f-strings, 20–21, 291–292

methods

lower(), 20

lstrip(), 22–23

removeprefix(), 23–24

removesuffix(), 25

rstrip(), 22–23

split(), 196–197

splitlines(), 186–187

strip(), 22–23

title(), 20

upper(), 20

multiline, 115

newlines in, 21–22

single and double quotes, 19, 24–25

tabs in, 21–22

variables in, 20–21

whitespace in, 21–23

strip() method, 22–23

strptime() method, 333–335

style guidelines, 68–69

blank lines, 69

CamelCase, 181

classes, 181

dictionaries, 96–97

functions, 153

if statements, 89

indentation, 68

line length, 69

PEP 8, 68

survey.py, 218

syntax errors, 24

avoiding with strings, 24–25

syntax highlighting, 16

tab (\t), 21–22

templates. See under Django

testing code, 209–223

assertions, 213, 217–218

failing tests, 214–216

full coverage, 212

naming tests, 213

passing tests, 212–214

pytest, 209–223

fixtures, 221–223

installing, 210–211

running tests, 213–214

test cases, 212

testing classes, 217–223

testing functions, 211–217

unit tests, 212

test_name_function.py, 212–217

test_survey.py, 220–223

text editors and IDEs. See also VS Code

Emacs and Vim, 475

Geany, 474

IDLE, 474

Jupyter Notebooks, 475

PyCharm, 475

Sublime Text, 474

third-party package, 210

toppings.py, 74, 82–83

tracebacks, 10, 17–18, 192, 195–196

try-except blocks. See exceptions

tuples, 65–67

defining, 65

for loop, 66–67

writing over, 67

type errors, 66

underscore (_)

in file and folder names, 10

in numbers, 28

in variable names, 17

unit tests, 212

user_profile.py, 148–149

values() method, 103–104

variables, 16–19, 28

constants, 28

as labels, 18–19

multiple assignment, 28

name errors, 17–18

naming conventions, 17

values, 16

venv module, 374–375

version control. See Git

virtual environments, 374–375

voting.py, 78–80

VS Code, 4–5

configuring, 470–473

features, 469–470

installing

on Linux, 9

on macOS, 8

on Windows, 6

Python extension, 9–10

opening files with Python, 185

Python extension, 9

running files, 10

shortcuts, 473–474

tabs and spaces, 471

weather data, 330–341. See also CSV files; Matplotlib

while loops, 117–126

active flag, 120–121

break statement, 121

continue statement, 122

infinite loops, 122–123

moving items between lists, 124

quit values, 118

removing all items from list, 125

whitespace, 21–23. See also strings

Windows

file paths, 186

Python

setting up, 5–6, 9–12, 463–464

troubleshooting installation, 10

terminals

running programs from, 12

starting Python session, 6

VS Code, installing, 6

word_count.py, 197–199

write_message.py, 190–191

write_text() method, 190–191

Zen of Python, 30–31

ZeroDivisionError, 192–195