Kick start to the world of Python

1. By
Karthik Prakash

2. • Introduction to Python
• Interactive “Shell”
• Basic Types and Containers
• Control Structures

3. “Remarkable power with very clear syntax”
Python is an Interpreted, Object Oriented
Programming language.
…it’s named after a television series Monty Python’s
Flying Circus
It was created by Guido Van Rossum in the year
1990…

4. Features :-
• Free and Open Source… Maintained by the PSF (Python Software
Foundation)
• Rapid Prototyping
• Compiled to interpreted byte code .. sometimes called as Scripting
language
….i.e Compilation is implicit
• Indentation for block structure
…“Life's better without braces(Bruce Eckel)”
• Extremely Portable (Windows,Linux,Unix,Mac… etc)
• Powerful Standard libraries

5. Two variations: IDLE (GUI) and PYTHON (command line)
• Most Python implementations work on CLI (Command Line Interface)
• Great for learning the language by experimenting with the library
• Great for testing your own modules
• Benefits of IDLE
• Multi Windows Text Editor
• Interactive Command Shell
• Syntax Highlighting
• Auto-Indentation
• Auto Completion extended to Intellisence

6. • None
• Numbers and Floats
• Complex Numbers …. (i + j)
• Floating point
• Boolean…. True or False
• “Strings”
• u“Unicode”
• Tuples ()
• Lists []
• Dictonaries {}
• Built-in Function “type()”

7. • If, else, elif….
• Try and except
• While Loop
• For Loop

8. • List Comprehension
• Functions
• Doc Strings
… Smart way of Documenting modules
• File Handling
…… read , write , append to file

9. Single
[ <item operation> for item in sequence <if condition>]
Nested
Special care has to be taken for the nested list
comprehension:
….when nesting list comprehensions, read from right to
left.

10. Function Definition :-
def name (arg1, arg2…. , argn)
“““ Documentation ””” #optional
statements
.
.
.
return expression
name(arg1,arg2) # Call to <name>

11. File Modes
• Mode Meaning
• 'r' open for reading (default)
• 'w' open for writing, truncating the file first
• 'a' open for writing, appending to the end of the file if it
exists
• 'b' binary mode

12. f = open(filename, [mode])
• read(), readline(), readlines()
• write(), writelines()
• seek(pos), tell()
• close()

13. • Classes
o Class Definition
o Class Objects
o Class Data members
o Class Methods
o Class Inheritance

14. class Stack:
"A well-known data structure…"
def __init__(self): # constructor
self.items = []
def push(self, x):
self.items.append(x) #. Push into the Stack…the sky is the limit
def pop(self):
x = self.items[-1] # Pop from the stack
del self.items[-1]
return x
def empty(self):
return len(self.items) == 0 # Boolean result

15. object = Stack() #--- Object of the Class “Stack”
….. Constructor invoked during Object instantiation
object.push(arg1) #---- Call to Class Method “push”
print object.items #---- Access the Class Data Member

16. • class BaseClass:
baseDataVar = 10
def baseMethods(self)
statements
class DerivedClass(BaseClass):
def Method()
print self.baseDataVar
self.baseMethods() #-- Call to base class method