Head First Python: A Learner's Guide to the Fundamentals of Python Programming, Third Edition, uses VS Code & Jupyter Notebook. 3 Ed

Cover....1

Title Page....4

Copyright....5

About the Author....7

Table of Contents....8

Intro: how to use this book....24

Who is this book for?....25

We know what you’re thinking....26

Metacognition: thinking about thinking....28

Here’s what WE did....29

Read Me ....31

Let’s install the latest Python....33

Python on its own is not enough....34

Configure VS Code to your taste....35

Add two required extensions to VS Code....36

VS Code’s Python support is state-of-the-art....37

The Technical Review Team....39

Acknowledgments....40

Chapter 0: why Python?....42

Getting ready to run some code....48

Preparing for your first Jupyter experience....49

Let’s pop some code into your notebook editor....50

Press Shift+Enter to run your code....51

What if you want more than one card?....56

Take a closer look at the card drawing code....58

The Big 4: list, tuple, dictionary, and set....59

Model your deck of cards with a set....60

The print dir combo mambo....61

Getting help with dir’s output....62

Populate the set with cards....63

This feels like a deck of cards now....65

What exactly is “card”?....66

Need to find something? ....69

Let’s pause and take stock....70

Python ships with a rich Standard Library....71

With Python you’ll only write the code you need....75

Just when you thought you were done…....82

Chapter 1: diving in....84

How is the Coach working right now?....86

The Coach needs a more capable stopwatch....87

Cubicle Conversation....89

The file and the spreadsheet are “related”....92

Our first task: Extract the filename’s data....93

A string is an object with attributes....94

Extract the swimmer’s data from the filename....99

Don’t try to guess what a method does…....100

Splitting (aka, breaking apart) a string....101

There’s still some work to do....103

Read error messages from the bottom up....107

Be careful when combining method calls....108

Cubicle Conversation....109

Let’s try another string method....110

All that remains is to create some variables....113

Task #1 is done!....118

Task #2: Process the data in the file....119

Chapter 2: lists of numbers....122

Task #2: Process the data in the file....123

Grab a copy of the Coach’s data....124

The open BIF works with files....125

Using with to open (and close) a file....126

Anatomy of with… open… as…....127

Variables are created dynamically, as needed....129

The file’s data is what you really want....130

We have the swimmer’s data from the file....132

Let’s take stock of our progress so far....133

What needs to happen next feels familiar....135

The previous chapter is paying dividends....138

Converting a time string into a time value....139

Convert the times to hundredths of seconds....140

To hundredths of seconds with Python....141

A quick review of Python’s for loop....143

The gloves are off… for loops vs. while loops....146

You’re cruising now and making great progress!....148

Let’s keep a copy of the conversions....149

Displaying a list of your list’s methods....150

It’s time to calculate the average....155

Convert the average to a swim time string....156

It’s time to bring everything together....160

Task #2 (finally) gets over the line!....163

Chapter 3: list of files....168

Cubicle Conversation....169

You already have most of the code you need....170

How to create a function in Python....171

Save your code as often as you wish....172

Simply copying code is not enough....173

Be sure to copy all the code you need....174

Use modules to share code....181

Bask in the glory of your returned data....182

Functions return a tuple when required....184

Let’s get a list of the Coach’s filenames....190

It’s time for a bit of detective work…....191

What can you do to lists?....192

Is the issue with your data or your code?....200

Cubicle Conversation....201

Decisions, decisions, decisions....204

Let’s look for the colon “in” the string....205

Did you end up with 60 processed files?....212

The Coach’s code is taking shape…....213

Chapter 4: formatted string literals....218

Cubicle Conversation....222

Getting from a simple chart to a Coach chart....226

Build the strings your HTML needs in code....227

String concatenation doesn’t scale....230

f-strings are a very popular Python feature....235

Generating SVG is easy with f-strings!....236

The data is all there, or is it?....237

Make sure you return all the data you need....238

You have numbers now, but are they usable?....239

All that’s left is the end of your webpage....248

Writing to files, like reading, is painless....249

It’s time to display your handiwork....252

All that’s left are two aesthetic tweaks…....253

It’s time for another custom function....255

Let’s add another function to your module....256

What’s with that hundredths value?....259

Rounding is not what you want (in this case)....260

Things are progressing well…....262

Chapter 5: getting organized....266

Let’s extract a list of swimmers’ names....268

The list-set-list duplicate removing trick....270

The Coach now has a list of names....272

A small change makes a “big” difference....273

Every tuple is unique....274

Perform super fast lookups with dictionaries....277

Dictionaries are key/value lookup stores....278

Anatomy of building a dictionary ....281

Dictionaries are optimized for speedy lookup....289

Display the entire dictionary....290

The pprint module pretty-prints your data....291

Your dictionary-of-lists is easily processed....292

This is really stating to come together....293

Chapter 6: building a webapp....300

Install Flask from PyPI....302

Prepare your folder to host your webapp....303

The Flask MVP....304

You have options when working with your code....306

Anatomy of the MVP Flask app....308

Building your webapp, bit by bit…....315

What’s the deal with that NameError?....320

Cubicle Conversation....321

Flask includes built-in session support....322

Flask’s session technology is a dictionary....323

Adjusting your code with the “better fix”....326

Building Jinja2 templates saves you time....332

Extend base.html to create more pages....334

Dynamically creating a drop-down list....337

Selecting a swimmer ....341

You need to somehow process the form’s data....342

Your form’s data is available as a dictionary....343

You’re inching closer to a working system....347

Functions support default parameter values....348

Default parameter values are optional....349

The final version of your code, 1 of 2....350

The final version of your code, 2 of 2....351

As a first webapp goes, this is looking good....353

The Coach’s system is ready for prime time....354

Chapter 7: deployment....358

There’s still something that doesn’t feel right....366

Jinja2 executes code between {{ and }}....371

Cubicle Conversation....372

The ten steps to cloud deployment....373

A beginner account is all you need....374

There’s nothing stopping you from starting…....375

When in doubt, stick with the defaults....376

The placeholder webapp doesn’t do much....377

Deploying your code to PythonAnywhere....378

Extract your code in the console....379

Configure the Web tab to point to your code....380

Edit your webapp’s WSGI file....381

Your cloud-hosted webapp is ready!....385

Chapter 8: working with HTML....390

The Coach needs more data....391

Cubicle Conversation....392

Get to know your data before scraping....393

We need a plan of action…....394

A step-by-step guide to web scraping....395

It’s time for some HTML-parsing technology....397

Grab the raw HTML page from Wikipedia....400

Get to know your scraped data....401

You can copy a slice from any sequence....403

Anatomy of slices, 1 of 3....404

Anatomy of slices, 2 of 3....405

Anatomy of slices, 3 of 3....406

It’s time for some HTML parsing power....411

Searching your soup for tags of interest....412

The returned soup is also searchable....413

Which table contains the data you need?....416

Four big tables and four sets of world records....418

It’s time to extract the actual data....419

Extract data from all the tables, 1 of 2....423

Extract data from all the tables, 2 of 2....424

That nested loop did the trick!....427

Chapter 9: working with data....430

Bending your data to your will…....431

You now have the data you need…....435

Apply what you already know…....437

Is there too much data here?....440

Filtering on the relay data....441

You’re now ready to update your bar charts....442

Cubicle Conversation....443

Python ships with a built-in JSON library....444

JSON is textual, but far from pretty....445

Getting to the webapp integration....449

All that’s needed: an edit and a copy’n’paste…....450

Adding the world records to your bar chart....451

Is your latest version of the webapp ready?....455

Cubicle Conversation....456

PythonAnywhere has you covered…....459

You need to upload your utility code, too....460

Deploy your latest webapp to PythonAnywhere....461

Tell PythonAnywhere to run your latest code....462

Test your utilities before cloud deployment....463

Let’s run your task daily at 1:00am....464

Chapter 9 1/2: working with elephants dataframes....468

The elephant in the room… or is it a panda?....469

A dictionary of dictionaries with pandas?....470

Start by conforming to convention....471

A list of pandas dataframes....472

Selecting columns from a dataframe....473

Dataframe to dictionary, attempt #1....474

Removing unwanted data from a dataframe....475

Negating your pandas conditonal expression....476

Dataframe to dictionary, attempt #2....477

Dataframe to dictionary, attempt #3....478

It’s another dictionary of dictionaries....479

Comparing gazpacho to pandas....483

It was only the shortest of glimpses…....489

Chapter 10: databases....492

The Coach has been in touch…....493

Cubicle Conversation....494

It pays to plan ahead…....496

Task #1: Decide on your database structure....498

The napkin structure + data....500

Installing the DBcm module from PyPI....501

Getting started with DBcm and SQLite....502

DBcm works alongside the “with” statement....503

Use triple-quoted strings for your SQL....505

Not all SQL returns results....507

Your tables are ready (and Task #1 is done)....512

Determining the list of swimmer’s files....513

Task #2: Adding data to a database table....514

Stay safe with Python’s SQL placeholders....516

Let’s repeat this process for the events....531

All that’s left is your times table…....535

The times are in the swimmer’s files…....536

A database update utility, 1 of 2....542

A database update utility, 2 of 2....543

Task #2 is (finally) done....544

Chapter 11: list comprehensions....548

Let’s explore the queries in a new notebook....551

Five lines of loop code become one....554

Getting from five lines of code to one…....555

A nondunder combo mambo....556

One query down, three to go…....561

Two queries down, two to go…....563

The last, but not least (query)…....564

The database utilities code, 1 of 2....569

The database utilities code, 2 of 2....570

It’s nearly time for the database integration....573

Cubicle Conversation....574

It’s time to integrate your database code!....581

Updating your existing webapp’s code....585

Review your template(s) for changes…....586

So… what’s the deal with your template?....589

Let’s display a list of events…....593

All that’s left is to draw the bar chart…....597

Reviewing the most-recent swimclub.py code....599

Meet the SVG-generating Jinja2 template....601

The convert_utils module....603

list zip… what?!?....606

Your database integrations are complete!....608

Chapter 12: deployment revisited....612

Cubicle Conversation....614

Migrating to MariaDB....616

Moving the Coach’s data to MariaDB....617

Apply three edits to schema.sql....618

Reusing your tables, 2 of 2....619

Let’s check your tables are defined correctly....620

Copying your existing data to MariaDB....621

Make your queries compatible with MariaDB....623

Your database utility code need edits, too....624

Create a new database on PythonAnywhere....627

Adjust your database credentials dictionary....628

Copying everything to the cloud....629

Update your webapp with your latest code....630

Just a few more steps…....631

Populate your cloud database with data....632

It’s time for a PythonAnywhere Test Drive....633

Is something wrong with PythonAnywhere?....635

Cubicle Conversation....636

The Coach is a happy chappy!....637

Appendix....642

1. Classes....643

2. Exceptions....646

3. Testing....647

4. The walrus operator....648

5. Where’s the switch? What switch?....649

6. Advanced language features....650

7. Concurrency....651

8. Type Hints....652

9. Virtual Environments....653

10. Tools....654

Index....656

Want to learn the Python language without slogging your way through how-to manuals? With Head First Python, you'll quickly grasp Python's fundamentals by working with built-in data structures and functions. You'll build your very own web app, which—once it's ready for prime time—runs in the cloud. You'll learn how to wrangle data with Python, scrape data from the web, feed data to pandas, and interact with databases. This third edition is a complete learning experience that will help you become a bona fide Python programmer in no time.

What's so special about this book?

If you've read a Head First book, you know what to expect: a visually rich format designed for the way your brain works. If you haven't, you're in for a treat. With this book, you'll learn Python through a multisensory experience that engages your mind—rather than a text-heavy approach that puts you to sleep.