Intro to Python

CSSU Nov/28/2007

By Georgi Petrov & Atanas Dyulgerov

Outline What is Python Python Advantages Who uses Python Syntax & Semantics Data Structures Python Standard Library Demo 1 Object Orientation Demo 2

What is Python? interpreted, interactive, object-oriented

programming language Widely used in the industry Cousin of Tcl, Perl and VB Used in web programming and in

standalone applications

Python Advantages Elegant syntax Safe Object-oriented Powerful Portable Free

Python is simple

print "Hello World!"

#include <iostream.h> int main() { cout << "Hello World!"; }

public class helloWorld {

public static void main(String [] args) { System.out.println("Hello World!"); }

}

Python

C++

Java

Python is fun & practical Lack of type declaration Huge library of modules Widespread use in industry Available for all the major platforms

(Windows, MacOS, Linux, Unix, BeOS, Java)

Who uses Python Google NASA Rackspace Industrial Light & Magic

Syntax - Indentation

Syntax - Operators Comparison Operators

==, <, >, <=, >= Logical Operators

Zero values are treated as “”, 0, None, 0.0, [] and {}

Data Structures Base Types

integer, float, long integer, octal integer, hexadecimal integer, complex, character string, list, dictionary, tuples, file

Collection typessequences & mappings

Object system

Python Standard Library The greatest strengths of Python Hundreds of modules Examples

Syntax: import email

email, math, calendar, HTMLParser

Object Oriented Mechanism Similar to C++

and Java Supports multiple

inheritance Polymorphism No private class

members

class Stack: def __init__(self,size): self.data = [None]*size self.size = 0  def push(self,item): self.data[self.size] = item self.size = self.size + 1   def pop(self): self.size = self.size - 1 return self.data[self.size]   def is_empty(self): return self.size == 0  def is_full(self): return self.size == len(self.data)

Demo 1 Adjusting Apache to read Python Sample “Hello World” script

Object Orientation Defining classes

class SomeClass: "Just some class...that's all."

Adding data members and methods class SomeClass

"Just some class...that's all."

someNumber = 2131

def someFunction ( self ):

return someNumber

Object Orientation

Self

Instantiating myObject = myClass()

Calling and addressing myObject.someFunction()

Deletion del myObject.someNumber

Object Orientation Constructors

class AnotherClass: def __init__ ( self, anotherArgument ): self.anotherArgument = anotherArgument

Single/Multiple Inheritance and Overriding class ParentClass: def print( self ): print “parent” class ChildClass ( ParentClass ): def print( self ): print “child”

Demo 2 Brief networking info Sockets SocketServer Framework Ports and Addresses Demo

References http://wiki.python.org http://www.python.org/ http://en.wikipedia.org/wiki/

Python_(programming_language)

Thank You

Q & A