1. director of PythonLabs at Zope Corporation
Guido van Rossum
director of PythonLabs at Zope Corporation

3. What’s in a name?
Snake logos and mascot notwithstanding, it’s named after Monty Python’s Flying Circus
Humor-impaired can safely ignore the spam references :-)
Nobody expects the Spanish inquisition

4. What is Python? O-O rapid prototyping language
Not just a scripting language
Not just another Perl
Easy to learn, read, use
Extensible (add new modules)
C/C++/Fortran/whatever
Java (through Jython)
Embeddable in applications

5. Touchy-feely properties
Open Source (OSI Certified)
copyrighted but use not restricted
no "viral" license
owned by independent non-profit, PSF
Mature (13 years old)
Supportive user community
plenty of good books, too
Simple design, easy to learn
reads like “pseudo-code”
Suitable as first language
Suitable as last language :-)

6. High-level properties
Extremely portable
Unix/Linux, Windows, Mac, PalmOS, WindowsCE, RiscOS, VxWorks, QNX, OS/2, OS/390, AS/400, PlayStation, Sharp Zaurus, BeOS, VMS…
Compiles to interpreted byte code
compilation is implicit and automatic
Memory management automatic
reference counting for most situations
GC added for cycle detection
“Safe”: no core dumps due to your bugs

7. What is it used for? rapid prototyping
web programming (client and server side)
ad hoc programming ("scripting")
steering scientific applications
extension language
XML processing
database applications
GUI applications
education

8. Who is using it? Google (various projects) NASA (several projects)
NYSE (one of only three languages "on the floor")
Industrial Light & Magic (everything)
Yahoo! (Yahoo mail & groups)
RealNetworks (function and load testing)
RedHat (Linux installation tools)
LLNL, Fermilab (steering scientific applications)
Zope Corporation (content management)
ObjectDomain (embedded Jython in UML tool)
Alice project at CMU (accessible 3D graphics)
More success stories at

9. Language properties Everything is an object
Packages, modules, classes, functions
Exception handling
Dynamic typing, polymorphism
Static scoping
Operator overloading
Indentation for block structure
Otherwise conventional syntax

10. High-level data types Numbers: int, long, float, complex
Strings, Unicode: immutable
Lists and dictionaries: containers
Other types for e.g. binary data, regular expressions, introspection
Extension modules can define new “built-in” data types

11. Interfaces to... XML Relational databases Java (via Jython)
DOM, expat
XMLRPC, SOAP, Web Services
Relational databases
MySQL, PostgreSQL, Oracle , ODBC, Sybase, Informix
Java (via Jython)
Objective C
COM, DCOM (.NET too)
Many GUI libraries
cross-platform
Tk, wxWindows, GTK, Qt
platform-specific
MFC, Mac (classic, Cocoa), X11

12. Compared to Perl Easier to learn More readable code
very important for infrequent users
More readable code
More maintainable code
Fewer “magical” side effects
More “safety” guarantees
Better Java integration

13. Compared to Java Code up to 5 times shorter Dynamic typing
and more readable
Dynamic typing
Multiple inheritance, operator overloading
Quicker development
no compilation phase
less typing
Yes, it may run a bit slower
but development is much faster
and Python uses less memory (studies show)
Similar (but more so) for C/C++

14. Jython Seamless integration with Java Separate implementation
Implements the same language
Different set of standard modules
differences in “gray areas”
e.g. some different introspection calls
different command line options, etc.

15. Jython's Java integration
Interactive
Compiles directly to Java bytecode
Import Java classes directly
Subclass Java classes
pass instances back to Java
Java beans integration
Can compile into Java class files

16. Example function def gcd(a, b): "greatest common divisor"
while a != 0:
a, b = b%a, a # parallel assignment
return b

17. Example class class Stack: "A well-known data structure" # doc string
def __init__(self): # constructor
self.items = []
def push(self, x):
self.items.append(x) # the sky is the limit
def pop(self):
x = self.items[-1] # what happens if it’s empty?
del self.items[-1]
return x
def empty(self):
return len(self.items) == 0

18. References and plugs References:
- Python home site
documentation, downloads, community, PSF
- success stories
- interview with GvR
- Zope community site
- Zope corporate site
Python Conferences (see
PyCon DC March Washington, DC
on-line registration ends today ($200)
Python UK April 2-3 Oxford, England
EuroPython June Charleroi, Belgium
Python11 at OSCON July 7-11 Portland, OR