1. PiTechnologies
Tudor Prodan
March 2009

3. What is Python
- a “very high-level language”
- developed by Guido van Rossum
- main features:
 simple, yet powerful semantics
 object-oriented, but multi-paradigm
 clean syntax and coherent design
 focus on productivity
 rich standard library
 lots of high quality 3rd-party
 several good implementations:
CPython, Pypy, IronPython (2.0.1), PyS60, Jython

4. Jython
Jython, lest you do not know of it, is the most
compelling weapon the Java platform has for its
survival into the 21st century :-)
—Sean McGrath, CTO, Propylon
July 31, 2003

5. CPython
Version history:
1.0 – Jan 1994
2.0 – Oct 2000
3.0 – Dec 2008
Latest stable versions:
2.6.1 and 3.0.1
Usable versions:
2.5.x
2.6.x = 2.5 + improvements + 3.0 features
(__future__)
| | |__ maintenance version
| |____ minor version
|______ major version

6. Why Python?

9. Why Python
 programming is fun again

10. Unfinished game
The problem of the unfinished game:
Let's say, hypothetically speaking,
you met someone who told you they had two children,
and one of them is a girl.
What are the odds that person has a boy and a girl?
-Jeff Atwood, December 30, 2008
http://www.codinghorror.com/blog

11. Unfinished game
Java

12. Unfinished game
C#

13. Unfinished game
Python

14. Unfinished game
LoC readable? fun?
Java 53 barely nope
C# 49 kind of not really
Python 10 clean, much more fun
concise than the above

15. Why Python
 programming is fun again
 agility
 elegance
 you don't have to fight the language

16. Why Python
Java is the COBOL of the 21st century.
-Sean Kelly, JPL, NASA

17. Spirit of C
Python is close to the “Spirit of C” (more than C++/
Java/...), as per ISO C Standard's “rationale”:
 trust the programmer
 don't prevent the programmer from doing what needs
to be done
 keep the language small and simple
 provide only one way to do an operation
 make it fast, even if it's not guaranteed to be
portable (the only bit not @100% in Python)

18. Python vs. C(++,#)/Java/..
 everything is a first-class object
- functions, methods, modules, ..
 typing: strong, but dynamic
- names have no type, objects have types
 no “declarations”, just statements
- implicit compilation, .pyc files
- everything is run-time (compile-time too)
 spare syntax, minimal ornamentation
- no { } for blocks
- no ( ) for conditions
- a lot less punctuation

19. Python vs. C(++,#)/Java/..
In the 1960's the KGB was very interested in learning everything
possible about the American space program, sending all sorts of
spies to find every possible piece of information.
One afternoon, a breathless spy returned to headquarters with a
piece of paper in his hand, excitedly shouting to his superior,
"Comrade! Comrade! The Americans are using Lisp to write their
rocket launching software!“
The commander was skeptical. "How do you know?"
"I broke into their research lab and stole a page from the
teletype machine! It's not the whole program, but it's the final
page and contains the concluding logic of the program! See for
yourself!"
The commander looked at the page and smiled:

20. Python vs. C(++,#)/Java/..
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21. Why Python
Example #2:
Create a Coordinate class
which holds a latitude and longitude,
to be used by a TelemetryTracker object.

22. Why Python
this example will show
Python vs. Java
but is actually
Python vs. Java / C# / PHP / (most others)

23. Why Python
Java:

24. Philosophy
You know you've reached perfection in design, not
when you have nothing more to add, but when you have
nothing more to take away.
-Antoine de Saint Exupery

25. Why Python
Java: Python:

26. Why Python
The Java guys will say:
 my IDE can generate most of that
- code is read a lot more than written

27. Why Python
The Java guys will say:
 my IDE can generate most of that
- code is read a lot more than written
 but, your fields are public
- Python philosophy

28. Why Python
The Java guys will say:
 my IDE can generate most of that
- code is read a lot more than written
 but, your fields are public
- Python philosophy
 can't we apply this to other languages?

29. Why Python
Java: Python:

30. Why Python
Eventually, the code will end up in production..
Java: Python:

31. Why Python
.. time passes ..

32. Why Python
.. time passes ..
Eventually,
decodeLat receives bad data
This is a bug!
What do we do?
- add a check

33. Why Python
Add a setter and a getter:

34. Why Python
Add a setter and a getter:
Let's try it out:

35. Why Python
and the TelemetryTracker code:
Python:
- still works
Java:
- needs modification

36. Why Python
in the end:
Python:
- gives you a choice
- you can even change your mind
Java/C#/PHP/..:
- no choice

37. Why Python
 programming is fun again
 agility
 elegance
 you don't have to fight the language
 the language trusts you
 .. it accommodates you

38. Why Python
 programming is fun again
 agility
 elegance
 you don't have to fight the language
 the language trusts you
 .. it accommodates you
 .. and will not go out of it's way to stop you

39. Why Python
Python has
lots &
LOTS
of good
books:

40. Why Python
 programming is fun again
 agility
 elegance
 you don't have to fight the language
 the language trusts you
 .. it accommodates you
 .. and will not go out of it's way to stop you
 good documentation (lots of books)
 good support: lots of forums, mailing lists, IRC

42. Why Python
Large number of high quality 3rd-party libraries and
frameworks:
- networking: twisted, cogen, concurrence
- scientific: NumPy, ScyPy, PyEvolve (genetic algorithms)
- testing: PyUnit, Google Mox
- fuzzing: Fuzz
- database: SQLAlchemy, Elixir, Django ORM
- web crawling: BeautifulSoup, lxml, Scrappy
- game development: PyGame
- GUI: PyGTK, wxPython, PyQt, GTK#
-templating: Genshi, Mako, Kid, Jinja2
- cryptography: M2Crypto, PyCrypto, Keyczar,
.. many, many others

43. Why Python
 programming is fun again
 agility
 elegance
 you don't have to fight the language
 the language trusts you
 .. it accommodates you
 .. and will not go out of it's way to stop you
 good documentation (lots of books)
 good support: lots of forums, IRC, mailing lists
 lots of high quality 3rd-party libraries

44. Why Python
But most interesting to us,
lots of great web frameworks:

45. Why Python
 programming is fun again
 agility
 elegance
 you don't have to fight the language
 the language trusts you
 .. it accommodates you
 .. and will not go out of it's way to stop you
 good documentation (lots of books)
 good support: lots of forums, IRC, mailing lists
 lots of high quality 3rd-party libraries
 many great web frameworks