You are previewing Head First Python.

Head First Python

Cover of Head First Python by Paul Barry Published by O'Reilly Media, Inc.
  1. Head First Python
  2. Dedication
  3. SPECIAL OFFER: Upgrade this ebook with O’Reilly
  4. A Note Regarding Supplemental Files
  5. Advance Praise for Head First Python
  6. Praise for other Head First books
  7. Author of Head First Python
  8. How to use This Book: Intro
    1. Who is this book for?
      1. Who should probably back away from this book?
    2. We know what you’re thinking
    3. We know what your brain is thinking
    4. Metacognition: thinking about thinking
    5. Here’s what WE did
    6. Here’s what YOU can do to bend your brain into submission
    7. Read Me
    8. The technical review team
    9. Acknowledgments
    10. Safari® Books Online
  9. 1. Meet Python: Everyone loves lists
    1. What’s to like about Python?
    2. Install Python 3
    3. Use IDLE to help learn Python
    4. Work effectively with IDLE
      1. TAB completion
      2. Recall code statements
      3. Edit recalled code
      4. Adjust IDLE’s preferences
    5. Deal with complex data
    6. Create simple Python lists
    7. Lists are like arrays
      1. Access list data using the square bracket notation
    8. Add more data to your list
    9. Work with your list data
      1. It’s time to iterate
    10. For loops work with lists of any size
    11. Store lists within lists
    12. Check a list for a list
    13. Complex data is hard to process
    14. Handle many levels of nested lists
    15. Don’t repeat code; create a function
    16. Create a function in Python
      1. What does your function need to do?
    17. Recursion to the rescue!
      1. What a great start!
    18. Your Python Toolbox
  10. 2. Sharing your Code: Modules of functions
    1. It’s too good not to share
    2. Turn your function into a module
    3. Modules are everywhere
    4. Comment your code
    5. Prepare your distribution
    6. Build your distribution
    7. A quick review of your distribution
    8. Import a module to use it
    9. Python’s modules implement namespaces
    10. Register with the PyPI website
    11. Upload your code to PyPI
    12. Welcome to the PyPI community
    13. With success comes responsibility
      1. Requests for change are inevitable
    14. Life’s full of choices
    15. Control behavior with an extra argument
      1. Take your function to the next level
    16. Before your write new code, think BIF
      1. The range() BIF iterates a fixed number of times
    17. Python tries its best to run your code
    18. Trace your code
    19. Work out what’s wrong
    20. Update PyPI with your new code
    21. You’ve changed your API
    22. Use optional arguments
    23. Your module supports both APIs
    24. Your API is still not right
    25. Your module’s reputation is restored
      1. Your Python skills are starting to build
    26. Your Python Toolbox
  11. 3. Files and Exceptions: Dealing with errors
    1. Data is external to your program
    2. It’s all lines of text
    3. Take a closer look at the data
    4. Know your data
    5. Know your methods and ask for help
    6. Know your data (better)
      1. The case of the missing colon
    7. Two very different approaches
    8. Add extra logic
    9. Handle exceptions
    10. Try first, then recover
      1. The try/except mechanism
    11. Identify the code to protect
    12. Take a pass on the error
    13. What about other errors?
      1. Handling missing files
    14. Add more error-checking code...
    15. ...Or add another level of exception handling
    16. So, which approach is best?
      1. Complexity is rarely a good thing
    17. You’re done...except for one small thing
    18. Be specific with your exceptions
    19. Your Python Toolbox
  12. 4. Persistence: Saving data to files
    1. Programs produce data
    2. Open your file in write mode
    3. Files are left open after an exception!
    4. Extend try with finally
    5. Knowing the type of error is not enough
    6. Use with to work with files
    7. Default formats are unsuitable for files
    8. Why not modify print_lol()?
    9. Pickle your data
    10. Save with dump and restore with load
      1. What if something goes wrong?
    11. Generic file I/O with pickle is the way to go!
    12. Your Python Toolbox
  13. 5. Comprehending data: Work that data!
    1. Coach Kelly needs your help
    2. Sort in one of two ways
    3. The trouble with time
    4. Comprehending lists
      1. The beauty of list comprehensions
    5. Iterate to remove duplicates
    6. Remove duplicates with sets
    7. Your Python Toolbox
  14. 6. Custom data Objects: Bundling code with data
    1. Coach Kelly is back (with a new file format)
    2. Use a dictionary to associate data
    3. Bundle your code and its data in a class
    4. Define a class
    5. Use class to define classes
      1. Creating object instances
    6. The importance of self
    7. Every method’s first argument is self
    8. Inherit from Python’s built-in list
    9. Coach Kelly is impressed
    10. Your Python Toolbox
  15. 7. Web Development: Putting it all together
    1. It’s good to share
      1. You’re a victim of your own success
    2. You can put your program on the Web
      1. A “webapp” is what you want
    3. What does your webapp need to do?
    4. Design your webapp with MVC
    5. Model your data
    6. View your interface
      1. YATE: Yet Another Template Engine
    7. Control your code
    8. CGI lets your web server run programs
    9. Display the list of athletes
    10. The dreaded 404 error!
    11. Create another CGI script
      1. But how do you know which athlete is selected?
    12. Enable CGI tracking to help with errors
    13. A small change can make all the difference
      1. It’s a small change, but it’s an important one
    14. Your webapp’s a hit!
    15. Your Python Toolbox
  16. 8. Mobile app Development: Small devices
    1. The world is getting smaller
      1. There’s more than just desktop computers out there
    2. Coach Kelly is on Android
      1. Run Python on the coach’s smartphone
    3. Don’t worry about Python 2
    4. Set up your development environment
      1. Download the Software Development Kit (SDK)
    5. Configure the SDK and emulator
      1. Add an Android platform
      2. Create a new Android Virtual Device (AVD)
    6. Install and configure Android Scripting
    7. Add Python to your SL4A installation
    8. Test Python on Android
      1. Take your Android emulator for a spin
    9. Define your app’s requirements
    10. The SL4A Android API
    11. Select from a list on Android
    12. The athlete’s data CGI script
      1. The complete Android app, so far
    13. The data appears to have changed type
    14. JSON can’t handle your custom datatypes
    15. Run your app on a real phone
      1. Step 1: Prepare your computer
      2. Step 2: Install AndFTP on your Android phone
    16. Configure AndFTP
    17. The coach is thrilled with his app
      1. Welcome to the future!
    18. Your Python Toolbox
  17. 9. Manage Your data: Handling input
    1. Your athlete times app has gone national
    2. Use a form or dialog to accept input
    3. Create an HTML form template
    4. The data is delivered to your CGI script
    5. Ask for input on your Android phone
    6. It’s time to update your server data
    7. Avoid race conditions
    8. You need a better data storage mechanism
    9. Use a database management system
    10. Python includes SQLite
    11. Exploit Python’s database API
    12. The database API as Python code
    13. A little database design goes a long way
    14. Define your database schema
    15. What does the data look like?
    16. Transfer the data from your pickle to SQLite
    17. What ID is assigned to which athlete?
    18. Insert your timing data
    19. SQLite data management tools
    20. Integrate SQLite with your existing webapp
    21. You still need the list of names
    22. Get an athlete’s details based on ID
    23. You need to amend your Android app, too
    24. Update your SQLite-based athlete data
    25. The NUAC is over the moon!
    26. Your Python Toolbox
  18. 10. Scaling your Webapp: Getting real
    1. There are whale sightings everywhere
    2. The HFWWG needs to automate
    3. Build your webapp with Google App Engine
    4. Download and install App Engine
      1. GAE uses Python 2.5
    5. Make sure App Engine is working
    6. App Engine uses the MVC pattern
    7. Model your data with App Engine
    8. What good is a model without a view?
      1. App Engine templates in an instant
    9. Use templates in App Engine
    10. Django’s form validation framework
    11. Check your form
    12. Controlling your App Engine webapp
      1. Improve the look of your form
    13. Restrict input by providing options
    14. Meet the “blank screen of death”
    15. Process the POST within your webapp
      1. App Engine handles requests as well as responses
    16. Put your data in the datastore
    17. Don’t break the “robustness principle”
    18. Accept almost any date and time
      1. There is a third option
      2. Use “db.StringProperty()” for dates and times
    19. It looks like you’re not quite done yet
    20. Sometimes, the tiniest change can make all the difference...
    21. Capture your user’s Google ID, too
    22. Deploy your webapp to Google’s cloud
    23. Your HFWWG webapp is deployed!
    24. Your Python Toolbox
  19. 11. Dealing with Complexity: Data wrangling
    1. What’s a good time goal for the next race?
    2. So... what’s the problem?
    3. Start with the data
      1. Take another look at the data
    4. Store each time as a dictionary
    5. Dissect the prediction code
    6. Get input from your user
      1. Use input() for input
    7. Getting input raises an issue...
    8. If it’s not in the dictionary, it can’t be found
    9. Search for the closest match
    10. The trouble is with time
    11. The time-to-seconds-to-time module
    12. The trouble is still with time...
    13. Port to Android
    14. Your Android app is a bunch of dialogs
      1. Get your Android app code ready
    15. Put your app together...
    16. Your app’s a wrap!
      1. And there’s no stopping you!
    17. Your Python Toolbox
    18. It’s time to go...
      1. This is just the beginning
  20. A. Leftovers: The Top Ten Things (we didn’t cover)
    1. #1: Using a “professional” IDE
    2. #2: Coping with scoping
    3. #3: Testing
    4. #4: Advanced language features
    5. #5: Regular expressions
    6. #6: More on web frameworks
    7. #7: Object relational mappers and NoSQL
      1. There’s NoSQL, too
    8. #8: Programming GUIs
    9. #9: Stuff to avoid
    10. #10: Other books
  21. Index
  22. About the Author
  23. SPECIAL OFFER: Upgrade this ebook with O’Reilly
  24. Copyright

Chapter 7. Web Development: Putting it all together

image with no caption

Sooner or later, you’ll want to share your app with lots of people. You have many options for doing this. Pop your code on PyPI, send out lots of emails, put your code on a CD or USB, or simply install your app manually on the computers of those people who need it. Sounds like a lot of work...not to mention boring. Also, what happens when you produce the next best version of your code? What happens then? How do you manage the update? Let’s face it: it’s such a pain that you’ll think up really creative excuses not to. Luckily, you don’t have to do any of this: just create a webapp instead. And, as this chapter demonstrates, using Python for web development is a breeze.

It’s good to share

image with no caption

You’re a victim of your own success

The new requests come flooding in right after Coach Kelly starts showing off your latest program. It appears that everyone wants access to the coach’s data!

The thing is: what’s the “best way” to do this?

You can put your program on the Web

image with no caption
image with no caption

A “webapp” is what you want

If you develop your program as a Web-based application (or ...

The best content for your career. Discover unlimited learning on demand for around $1/day.