Head First Python

Description

Ever wished you could learn Python from a book? Head First Python is a complete learning experience for Python that helps you learn the language through a unique method that goes beyond syntax and how-to manuals, helping you understand how to be a great Python programmer. You'll quickly learn the language's fundamentals, then move onto persistence, exception handling, web development, SQLite, data wrangling, and Google App Engine. You'll also learn how to write mobile apps for Android, all thanks to the power that Python gives you. We think your time is too valuable to waste struggling with new concepts. Using the latest research in cognitive science and learning theory to craft a multi-sensory learning experience, Head First Python uses a visually rich format designed for the way your brain works, not a text-heavy approach that puts you to sleep. Table of Contents How to use this book: Intro Who is this book for? We know what you’re thinking We know what your brain is thinking Metacognition: thinking about thinking Here’s what WE did: Here’s what YOU can do to bend your brain into submission Read Me The technical review team Acknowledgments Safari® Books Online HERE LOL HERE 1. Meet Python: Everyone Loves Lists What’s to like about Python? Install Python 3 Use IDLE to help learn Python Work effectively with IDLE Deal with complex data Create simple Python lists Lists are like arrays Add more data to your list Work with your list data For loops work with lists of any size Store lists within lists Check a list for a list Complex data is hard to process Handle many levels of nested lists Don’t repeat code; create a function Create a function in Python Recursion to the rescue! Your Python Toolbox 2. Sharing Your Code: Modules of Functions It’s too good not to share Turn your function into a module Modules are everywhere Comment your code Prepare your distribution Build your distribution A quick review of your distribution Import a module to use it Python’s modules implement namespaces Register with the PyPI website Upload your code to PyPI Welcome to the PyPI community With success comes responsibility Life’s full of choices Control behavior with an extra argument Before your write new code, think BIF Python tries its best to run your code Trace your code Work out what’s wrong Update PyPI with your new code You’ve changed your API Use optional arguments Your module supports both APIs Your API is still not right Your module’s reputation is restored Your Python Toolbox 3. Files and Exceptions: Dealing with Errors Data is external to your program It’s all lines of text Take a closer look at the data Know your data Know your methods and ask for help Know your data (better) Two very different approaches Add extra logic Handle exceptions Try first, then recover Identify the code to protect Take a pass on the error What about other errors? Add more error-checking code… …Or add another level of exception handling So, which approach is best? You’re done…except for one small thing Be specific with your exceptions Your Python Toolbox 4. Persistence: Saving Data to Files Programs produce data Open your file in write mode Files are left open after an exception! Extend try with finally Knowing the type of error is not enough Use with to work with files Default formats are unsuitable for files Why not modify print lol()? Pickle your data Save with dump and restore with load Generic file I/O with pickle is the way to go! Your Python Toolbox 5. Comprehending Data: Work that Data! Coach Kelly needs your help Sort in one of two ways The trouble with time Comprehending lists Iterate to remove duplicates Remove duplicates with sets Your Python Toolbox 6. Custom Data Objects: Bundling code with Data Coach Kelly is back (with a new file format) Use a dictionary to associate data Bundle your code and its data in a class Define a class Use class to define classes The importance of self Every method’s first argument is self Inherit from Python’s built-in list Coach Kelly is impressed Your Python Toolbox 7. Web Development: Putting It All Together It’s good to share You can put your program on the Web What does your webapp need to do? Design your webapp with MVC Model your data View your interface Control your code CGI lets your web server run programs Display the list of athletes The dreaded 404 error! Create another CGI script Enable CGI tracking to help with errors A small change can make all the difference Your webapp’s a hit! Your Python Toolbox 8. Mobile App Development. Small Devices The world is getting smaller Coach Kelly is on Android Don’t worry about Python 2 Set up your development environment Configure the SDK and emulator Install and configure Android Scripting Add Python to your SL4A installation Test Python on Android Define your app’s requirements The SL4A Android API Select from a list on Android The athlete’s data CGI script The data appears to have changed type JSON can’t handle your custom datatypes Run your app on a real phone Configure AndFTP The coach is thrilled with his app Your Python Toolbox 9. Manage Your Data: Handling Input Your athlete times app has gone national Use a form or dialog to accept input Create an HTML form template The data is delivered to your CGI script Ask for input on your Android phone It’s time to update your server data Avoid race conditions You need a better data storage mechanism Use a database management system Python includes SQLite Exploit Python’s database API The database API as Python code A little database design goes a long way Define your database schema What does the data look like? Transfer the data from your pickle to SQLite What ID is assigned to which athlete? Insert your timing data SQLite data management tools Integrate SQLite with your existing webapp You still need the list of names Get an athlete’s details based on ID You need to amend your Android app, too Update your SQLite-based athlete data The NUAC is over the moon! Your Python Toolbox 10. Scaling Your Webapp: Getting Real There are whale sightings everywhere The HFWWG needs to automate Build your webapp with Google App Engine Download and install App Engine Make sure App Engine is working App Engine uses the MVC pattern Model your data with App Engine What good is a model without a view? Use templates in App Engine Django’s form validation framework Check your form Controlling your App Engine webapp Restrict input by providing options Meet the “blank screen of death” Process the POST within your webapp Put your data in the datastore Don’t break the “robustness principle” Accept almost any date and time It looks like you’re not quite done yet Sometimes, the tiniest change can make all the difference… Capture your user’s Google ID, too Deploy your webapp to Google’s cloud Your HFWWG webapp is deployed! Your Python Toolbox 11. Dealing with Complexity: Data Wrangling What’s a good time goal for the next race? So…what’s the problem? Start with the data Store each time as a dictionary Dissect the prediction code Get input from your user Getting input raises an issue… If it’s not in the dictionary, it can’t be found. Search for the closest match The trouble is with time The time-to-seconds-to-time module The trouble is still with time… Port to Android Your Android app is a bunch of dialogs Put your app together… Your app’s a wrap! Your Python Toolbox It’s time to go… Appendix: Leftovers: The Top Ten Things (we didn't cover) #1: Using a “professional” IDE #2: Coping with scoping #3: Testing #4: Advanced language features #5: Regular expressions #6: More on web frameworks #7: Object relational mappers and NoSQL #8: Programming GUIs #9: Stuff to avoid #10: Other books Index