object-class_in python programming .pptx

Object-Oriented
Approach in
Python
Programming
Presented By
PRIYANKA GHOSE,
Information Technology,
GCETT, Serampure

Object-Oriented Approach in Python
cont.
Object-Oriented Approach:
Custom Classes: Attributes
The Object-Oriented
Approach, and Methods,
Inheritance and
Polymorphism, Using Properties to Control Attribute
Access.
Exception Handler, Catching
Exceptions and tools:
Default Exceptions,
Raising
Exceptions, User-Defined Exceptions,
Termination
Actions.

cont
.
The Object-Oriented Approach :
▶ One of the popular approaches to solve a programming problem
is by creating objects. This is known as Object-Oriented
Programming (OOP).
▶ An object has two characteristics:
1. Attributes
2. Behavior
▶ A parrot can be an object, as it has the following properties:
▶name, age, color as attributes
▶singing, dancing as behavior
▶ The concept of OOP in Python focuses on creating reusable code.
This concept is also known as DRY (Don't Repeat Yourself).

cont.
Object-Oriented vs Procedural :
Sl.
No
Object-oriented Programming Procedural Programming
1. Object-oriented programming is the problem-solving
approach and used where computation is done by
using objects.
Procedural programming uses a list of instructions
to do computation step by step.
2. It makes the development and maintenance easier. In procedural programming, It is not easy to
maintain the codes when the project becomes
lengthy.
3. It simulates the real world entity. So real-world
problems can be easily solved through oops.
It doesn't simulate the real world. It works on step
by step instructions divided into small parts called
functions.
4. It provides data hiding. So it is more secure than
procedural languages. You cannot access private data
from anywhere.
Procedural language doesn't provide any
proper way for data binding, so it is less secure.

Object-Oriented Approach in Python cont.
Custom Classes:
▶ Class − A user-defined prototype for an object that defines a
set of attributes that characterize any object of the class. The
attributes are data members (class variables and instance
variables) and methods, accessed via dot notation.
How to Define a Class?
▶ All class definitions start with the class keyword, which is
followed by the name of the class and a colon. Any code that is
indented below the class definition is considered part of the
class’s body.
class class_name:
#Code_1
#Code_2
#Code_3 Note: Not part of the class

Object
▶ An object (instance) is an instantiation of a class. When class is
defined, only the description for the object is defined.
Therefore, no memory or storage is allocated.

Custom Functions
Attributes and Methods
▶ Methods are functions defined inside the body of a class. They are used to define the
behaviors of an object.
▶ A method in python is somewhat similar to a function, except it is associated with
object/classes. Methods in python are very similar to functions except for two major
differences.
1. The method is implicitly used for an object for which it is called.
2. The method is accessible to data that is contained within the class.
General Syntax:
class ClassName:
def method_name( ):
…………..
# Method_body
………………
▶ **Note** Before writing any function, check if that function is already written or included in the python

cont. class car:
def init (self,
modelname, year):
self.modelname = modelname
self.year = year
def display(self):
print(self.modelname,self.year)
c1 = car(“Nexon", 2016) # Object creation
c1.display( )
▶ init ( ) any number of parameters, but the first
parameter will always be a variable called self.
▶ When a new class instance is created, the instance is automatically
passed to the self parameter in . init ( ) so that new

Types Of Variables
 Instance variables
 Class / Static variables
Instance Variables:

Types Of Variables
Class Variables

Types of Methods
Static Methods

Inner Class
Program: Version-1

Object-Oriented Programming
cont.
Inheritance
▶ Inheritance is a way of creating a new class for using details of
an existing class without modifying it.
▶ The newly formed class is a derived class (or child
class).

Encapsulation
▶ Using OOP in Python, we can restrict access to
methods and variables.
▶ This prevents data from direct modificationwhichis
called encapsulation.
▶ In Python, we denote private attributes using underscore as the
prefix i.e single _ or double .

Polymorphism
▶ Polymorphism is an ability(in OOP) to use
a common interface for multiple forms (data types).

Access Specifiers & Data Abstraction
What is Data Abstraction?
Data Abstraction in Python is the process of hiding the real implementation of an application from
the user and emphasizing only on usage of it.
▶ E.g. when you use mobile, we need not know how pressing a key changes the volume level. We
just need to know that pressing up button increases the volume and the down button reduces
the volume.
Why Do We Need Abstraction?
Through the process of abstraction in Python, a programmer can hide all the irrelevant data/process
of an application in order to reduce complexity, provide security and increase the efficiency.
How is Abstraction achieved?
▶ Abstraction is achieved with the help of access specifiers.

▶ Using Properties to Control Attribute Access.
class Mydata:
# constructor
def init (self, name, gender, age
):
# public data mambers
self.myName = name
self._myGender =
gender self. myAge =
age
# public memeber
function
def displayData(self):
# accessing public data
member print(“Name: ",
self.myName)
# accessing protected data
member print(“Gender: ",
self._myGender) # accessing
private data member
print(“Age: ", self. myAge)
# creating object of the class
obj = Mydata("Rani", “Female",
21)
# calling public member function of the
class obj.displayData()
# accessing public data member
print("Name: ", obj.myName)
# accessing protected data
member print(“Gender: ",
obj.myGender) # accessing
private data member
OUTPUT:
Name: Rani
Gender: Female
AttributeError: ‘Mydata'
object has no
attribute ' age'

Key Points to Remember:
▶ Object-Oriented Programming makesthe program
easy to understand as well as efficient.
▶ Since the class is sharable, the code can be reused.
▶ Data is safe and secure with data abstraction.
▶ Polymorphism allows the same interface for different objects,
so programmers can write efficient code.

object-class_in python programming .pptx

object-class_in python programming .pptx

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object-class_in python programming .pptx