Head First Python

Table of Contents......Page 11
How to use this book: Intro......Page 25
Who is this book for?......Page 26
We know what your brain is thinking......Page 27
Metacognition: thinking about thinking......Page 29
Here’s what WE did:......Page 30
Here’s what YOU can do to bend your brain into submission......Page 31
Read Me......Page 32
The technical review team......Page 34
Acknowledgments......Page 35
Safari® Books Online......Page 36
1. Meet Python: Everyone Loves Lists......Page 37
What’s to like about Python?......Page 38
Install Python 3......Page 39
Use IDLE to help learn Python......Page 40
Work effectively with IDLE......Page 41
Deal with complex data......Page 42
Create simple Python lists......Page 43
Lists are like arrays......Page 45
Add more data to your list......Page 47
Work with your list data......Page 51
For loops work with lists of any size......Page 52
Store lists within lists......Page 54
Check a list for a list......Page 56
Complex data is hard to process......Page 59
Handle many levels of nested lists......Page 60
Don’t repeat code; create a function......Page 64
Create a function in Python......Page 65
Recursion to the rescue!......Page 67
Your Python Toolbox......Page 68
2. Sharing Your Code: Modules of Functions......Page 69
It’s too good not to share......Page 70
Turn your function into a module......Page 71
Modules are everywhere......Page 72
Comment your code......Page 73
Prepare your distribution......Page 76
Build your distribution......Page 77
A quick review of your distribution......Page 78
Import a module to use it......Page 79
Python’s modules implement namespaces......Page 81
Register with the PyPI website......Page 83
Upload your code to PyPI......Page 84
Welcome to the PyPI community......Page 85
With success comes responsibility......Page 86
Life’s full of choices......Page 87
Control behavior with an extra argument......Page 88
Before your write new code, think BIF......Page 89
Python tries its best to run your code......Page 93
Trace your code......Page 94
Work out what’s wrong......Page 95
Update PyPI with your new code......Page 96
You’ve changed your API......Page 98
Use optional arguments......Page 99
Your module supports both APIs......Page 101
Your API is still not right......Page 102
Your module’s reputation is restored......Page 106
Your Python Toolbox......Page 107
3. Files and Exceptions: Dealing with Errors......Page 109
Data is external to your program......Page 110
It’s all lines of text......Page 111
Take a closer look at the data......Page 113
Know your data......Page 115
Know your methods and ask for help......Page 116
Know your data (better)......Page 118
Two very different approaches......Page 119
Add extra logic......Page 120
Handle exceptions......Page 124
Try first, then recover......Page 125
Identify the code to protect......Page 127
Take a pass on the error......Page 129
What about other errors?......Page 132
Add more error-checking code…......Page 133
…Or add another level of exception handling......Page 134
So, which approach is best?......Page 135
You’re done…except for one small thing......Page 137
Be specific with your exceptions......Page 138
Your Python Toolbox......Page 139
4. Persistence: Saving Data to Files......Page 141
Programs produce data......Page 142
Open your file in write mode......Page 146
Files are left open after an exception!......Page 150
Extend try with finally......Page 151
Knowing the type of error is not enough......Page 153
Use with to work with files......Page 156
Default formats are unsuitable for files......Page 160
Why not modify print lol()?......Page 162
Pickle your data......Page 168
Save with dump and restore with load......Page 169
Generic file I/O with pickle is the way to go!......Page 173
Your Python Toolbox......Page 174
5. Comprehending Data: Work that Data!......Page 175
Coach Kelly needs your help......Page 176
Sort in one of two ways......Page 180
The trouble with time......Page 184
Comprehending lists......Page 191
Iterate to remove duplicates......Page 197
Remove duplicates with sets......Page 202
Your Python Toolbox......Page 208
6. Custom Data Objects: Bundling code with Data......Page 209
Coach Kelly is back (with a new file format)......Page 210
Use a dictionary to associate data......Page 214
Bundle your code and its data in a class......Page 225
Define a class......Page 226
Use class to define classes......Page 227
The importance of self......Page 228
Every method’s first argument is self......Page 229
Inherit from Python’s built-in list......Page 240
Coach Kelly is impressed......Page 247
Your Python Toolbox......Page 248
7. Web Development: Putting It All Together......Page 249
It’s good to share......Page 250
You can put your program on the Web......Page 251
What does your webapp need to do?......Page 254
Design your webapp with MVC......Page 257
Model your data......Page 258
View your interface......Page 262
Control your code......Page 270
CGI lets your web server run programs......Page 271
Display the list of athletes......Page 272
The dreaded 404 error!......Page 278
Create another CGI script......Page 280
Enable CGI tracking to help with errors......Page 284
A small change can make all the difference......Page 286
Your webapp’s a hit!......Page 288
Your Python Toolbox......Page 289
8. Mobile App Development. Small Devices......Page 291
The world is getting smaller......Page 292
Coach Kelly is on Android......Page 293
Don’t worry about Python 2......Page 295
Set up your development environment......Page 296
Configure the SDK and emulator......Page 297
Install and configure Android Scripting......Page 298
Add Python to your SL4A installation......Page 299
Test Python on Android......Page 300
Define your app’s requirements......Page 302
The SL4A Android API......Page 310
Select from a list on Android......Page 314
The athlete’s data CGI script......Page 317
The data appears to have changed type......Page 320
JSON can’t handle your custom datatypes......Page 321
Run your app on a real phone......Page 324
Configure AndFTP......Page 325
The coach is thrilled with his app......Page 326
Your Python Toolbox......Page 327
9. Manage Your Data: Handling Input......Page 329
Your athlete times app has gone national......Page 330
Use a form or dialog to accept input......Page 331
Create an HTML form template......Page 332
The data is delivered to your CGI script......Page 336
Ask for input on your Android phone......Page 340
It’s time to update your server data......Page 344
Avoid race conditions......Page 345
You need a better data storage mechanism......Page 346
Use a database management system......Page 348
Python includes SQLite......Page 349
Exploit Python’s database API......Page 350
The database API as Python code......Page 351
A little database design goes a long way......Page 352
Define your database schema......Page 353
What does the data look like?......Page 354
Transfer the data from your pickle to SQLite......Page 357
What ID is assigned to which athlete?......Page 358
Insert your timing data......Page 359
SQLite data management tools......Page 362
Integrate SQLite with your existing webapp......Page 363
You still need the list of names......Page 368
Get an athlete’s details based on ID......Page 369
You need to amend your Android app, too......Page 378
Update your SQLite-based athlete data......Page 384
The NUAC is over the moon!......Page 385
Your Python Toolbox......Page 386
10. Scaling Your Webapp: Getting Real......Page 387
There are whale sightings everywhere......Page 388
The HFWWG needs to automate......Page 389
Build your webapp with Google App Engine......Page 390
Download and install App Engine......Page 391
Make sure App Engine is working......Page 392
App Engine uses the MVC pattern......Page 395
Model your data with App Engine......Page 396
What good is a model without a view?......Page 399
Use templates in App Engine......Page 400
Django’s form validation framework......Page 404
Check your form......Page 405
Controlling your App Engine webapp......Page 406
Restrict input by providing options......Page 412
Meet the “blank screen of death”......Page 414
Process the POST within your webapp......Page 415
Put your data in the datastore......Page 416
Don’t break the “robustness principle”......Page 420
Accept almost any date and time......Page 421
It looks like you’re not quite done yet......Page 424
Sometimes, the tiniest change can make all the difference…......Page 425
Capture your user’s Google ID, too......Page 426
Deploy your webapp to Google’s cloud......Page 427
Your HFWWG webapp is deployed!......Page 430
Your Python Toolbox......Page 431
11. Dealing with Complexity: Data Wrangling......Page 433
What’s a good time goal for the next race?......Page 434
So…what’s the problem?......Page 436
Start with the data......Page 437
Store each time as a dictionary......Page 443
Dissect the prediction code......Page 445
Get input from your user......Page 449
Getting input raises an issue…......Page 450
If it’s not in the dictionary, it can’t be found.......Page 451
Search for the closest match......Page 452
The trouble is with time......Page 454
The time-to-seconds-to-time module......Page 455
The trouble is still with time…......Page 458
Port to Android......Page 460
Your Android app is a bunch of dialogs......Page 461
Put your app together…......Page 465
Your app’s a wrap!......Page 467
Your Python Toolbox......Page 468
It’s time to go…......Page 469
Appendix: Leftovers: The Top Ten Things (we didn\'t cover)......Page 471
#1: Using a “professional” IDE......Page 472
#2: Coping with scoping......Page 473
#3: Testing......Page 474
#4: Advanced language features......Page 475
#5: Regular expressions......Page 476
#6: More on web frameworks......Page 477
#7: Object relational mappers and NoSQL......Page 478
#8: Programming GUIs......Page 479
#9: Stuff to avoid......Page 480
#10: Other books......Page 481
Index......Page 483