Python: Object oriented programming, RTS Tech. Indore This is a presentation to take your skills to next level. Hope you will like our work to make programming easier for you. Feel free to contact for the online/offline batches.

1. 1
Python
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2. 1
Object Oriented Programming
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3. Object Oriented Programming concept
 Module
 Class
 Object
 Encapsulation
 Inheritance
 Abstraction
 Polymorphism
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4. Application
• One application is made of multiple modules
• A Module is a file with .py extension.
• A module can define functions, classes and
variables.
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5. Module
 Module is a file of .py extension
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6. 6
Student.py
Following is Student module which contains two methods add()
and update( )
o def add_student( rollno, Name ):
o print("Adding Student")
o print('Name', Name )
o print(‘Rollno', rollno )
o return
o def update_student(Name ):
o print("Updating Student")
o print('Name', Name )
o return
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7. 7
• You can import a module by import statement
in python program. We are importing
Student.py module in TestStudent.py file.
o import Student
• Now we can use module functions:
o Student.add_student(1,”Sonu”)
o Student.add_student(2,”Monu”)
TestStudent.py
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8. from ... Import statement
 We can import specific functions from a module using
from ...import statement.
o from Student import add,update
o add(1,"Ram")
o update("Shyam")
 You can import all methods using * character
 from Student import *
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9. Module search path
 When you import a module, python interpreter searches
module in different directories in the following sequences:
 The current directory.
 If module is not found then searches each directory specified
 in environment variable PYTHONPATH.
 If all fails then python checks the default path.
 You can set PYTHONPATH as per your app requirements
 set PYTHONPATH =c:pythonlibl;c:pythonlib2;
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10. Objects: Real world Entities
 Object=Related attributes+ Related methods
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11. Objects vs Class
Attributes
• Color
• Brand
• Price
• …
Method
• take_Selfie()
• Calling()
• Messaging()
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Virtual Entity Actual Entity

12. Class
 It is a structure of an Object.
 Class contains related attributes and methods of an
Object.
 Class keyword is used to define a class.
 Class contains the complete details about an object.
 Ex.
 Home
 Pen
 Chair
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13. Object
• When we create a class only description is created no
memory is allocated.
• We can create an variable of the class.
• Variable is known as object(instance).
• We can create multiple object of the class.
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14. Define a class
 ‘class’ keyword is used to define the class.
 Class Mobile:
 ‘contains all details about mobile’
 The first line after the class name is a document String.
 Class Members:
 Attributes
 Methods
 Constructor
 Destructor
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15. Mobile
 class Mobile:
 "contains mobile information“
 #class variables are shared by all instance
 object_count=0
 def __init__(self):#constructor
 self.color = "" #instance attribute
 self.brand=“”
 Mobile.object_count+=1
 def get_color(self): #instance Method
 return self.color
 def set_color(self,color):
 self.color = color
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16. TestMobile.py
 Create Object(variable) of Mobile class.
 We can create multiple object of the class.
 m1=Mobile()
 m2=Mobile()
 m1.set_color("black")
 Print Value of the Mobile
 print("Count",Mobile.object_count)
 print("color: ",m1.get_color())
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17. Built in Class Attributes
 __doc__: to get doc string of the class.
 __dict__: to get dictionary of the class members.
 __bases__: to get base classes tuple.
 __name__: to get class name.
 __module__: to get module name.
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18. Class attributes
 print("Dictonary:",Mobile.__dict__)
 print("Name:",Mobile.__name__)
 print("Document string:",Mobile.__doc__)
 print("Module:",Mobile.__module__)
 print("Bases:",Mobile.__bases__)
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19. Class(static) attributes
 Class attributes are declared within a class but outside
method.
 class Mobile:
 object_count=0
 It is shared by all instance of the class.
 Static variables got memory one time.
 We can access class variable by class name.
 Mobile.object_count+=1
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20. Instance (non-static) Attributes
 Instance variables are define inside the constructor.
 def __init__(self):#constructor
 self.color =""
 self.brand=“”
 Instance variable get memory for each instance
separately.
 We can access instance variable with the instance name.
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21. Constructor
 Constructor is defined by __init__(self) method.
 Each class has only one constructor method.
 Constructor is used to initialize the class and instance
variable.
 It is executed at the time of object creation(instantiation
process).
 self keyword represent current instance.
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22. Methods in a class
 Method is used to write business logic.
 Method is define by def keyword.
 Instance method contains a self attribute to access
instance variable.
 Class method does not require self keyword.
 We can access class method with the help of class name
 class Mobile:
 def get_color(self):
 return self.color
 def set_color(self,color):
 self.color = color
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23. __del__(self)
 Destructor function remove an object from the memory.
 __del__() method is used to create destructor in a class.
 When an object is not in use the destructor function is
automatically called.
 def __del__(self):
 name=self.__class__.__name__
 print("Object is Destroyed {}".format(name))
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24. Object to string
 We can convert an object into string form.
 __str__(self) method is used to create an string function in
a class.
 When we print an object the address is printed
 <__main__.Mobile object at 0x000001EA4D8670D0>
 after creating __str__(self) method in a class , when we
print an object the object is automatically converted into
string representation.
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25. Inheritance
 It is a concept of OOP language.
 It is use to define a class based on another class.
 One class is known as Base or super class and another class is
known as Derived or sub class.
 Here Person is a Base class and Programmer, Doctor are Derived
classes.
 By default Each class has Object as Base Class.
 Syntax: class Doctor(Person):
 pass
Person
Programmer Doctor
Person
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26. Types of Inheritance
Class A
Class B Class C
Class B
Class A
Class C
Class B
Class A Class A
Class B Class C
1.Single Level 2.Multi Level 3.Multiple 4. Hierarchical
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27. Mobile
:
+IMEI:int
-brand:String
-color:String
-price:int
+getBrand():String
+setBrand():
:
-keypad:boolean
-radio:Boolean
+playRadio()
:
-ScreenSize:int
-osType:String
+setScreenSize():
+getScreenSize():int
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:
+IMEI:int
-brand:String
-color:String
-price:int
+getBrand():String
+setBrand():

28. Mobile class
 class Mobile:
 counts=0
 def __init__(self, name=None,color=None,im=0,price=0):
 self.__name = name
 self.__color = color
 self.__price = price
 self.__IMEI = im
 Mobile.counts+=1
 #setter and getter methods
 def get_color(self):
 return self.__color
 def set_color(self, color):
 self.__color = color
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29. BasicPhone class
 from mobile import Mobile
 class BasicPhone(Mobile):
 def __init__(self):
 self.__keypad=“”

def get_keypad(self):
 return self.__keypad
 def set_keypad(self,keypad):
 self.__keypad =keypad
 def tuneRadio(self):
 return "Tunning radio"
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30. Create child class Instance
 from basicPhone import BasicPhone
 phone = BasicPhone()
 phone.setColor("Black")
 phone.setBrandName("Nokia")
 phone.setPrice(2000)
 phone.setKeypad(True)

print("--------Phone Info-------------")
 print("Color ={}".format(phone.getColor()))
 print("BrandName ={}".format(phone.getbrand()))
 print("Price ={}".format(phone.getPrice()))
 print("Radio {}".format(phone.tuneRadio()))
 print("Keypad:{}".format(phone.get_keypad()))
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31. How to call Parent Class Constructor?
 from mobile import Mobile
 class SmartPhone(Mobile):
 def __init__(self,n,c,i,p,screen_size):
 self.__screen_size=screen_size
 # super(SmartPhone,self).__init__(n,c,i,p
 #OR
 super().__init__(n,c,i,p)
 def get_ScreenSize(self):
 return self.__screen_size
 def set_ScreenSize(self,screen_size):
 self.__screen_size = screen_size
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32. Parent class constructor
 from smartPhone import SmartPhone
 sp=SmartPhone("REalMe","Black",12345671,20000,20)
 print("Price {}".format(sp.get_price()))
 print("Color {}".format(sp.get_color()))
 print("IMEI No {}".format(sp.get_IMEI()))
 print("Screen Size {}".format(sp.get_ScreenSize()))
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33. Polymorphism
 Having many Forms.
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34. Types of polymorphism
 Runtime
 Method Overriding
 Compile time
 Method Overloading
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35. Method Overriding
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:
-keypad:boolean
-radio:Boolean
+answerCall()
:
-ScreenSize:int
-osType:String
+answerCall()
:
+IMEI:int
-brand:String
-color:String
-price:int
+getBrand():String
+setBrand():
+answerCall()

36. Method Overriding(cont.)
 Sub class can override the Super class Method.
 class Mobile:
 def answer(self):
 print("Answer the call")
 class BasicPhone:
 def answer(self):
 print(“Press the key to answer the call")
 class SmartPhone:
 def answer(self):
 print(“Swipe right to answer the call")
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37. Abstraction
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38. Abstract class
 Abstract class contains abstract method.
 Abstract method has only method declaration no method
definition
 Different mobile phone has different implementation for
answerCall() method.
 We can not create instance of abstract class.
 Child class will provide implementation to the abstract
method.
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39. Implementation
 from abc import ABC,abstractmethod
 class Mobile(ABC):
 @abstractmethod
 def answerCall(self):
 pass
 class BasicPhone:
 def answer(self):
 print(“Press the key to answer the call")
 class SmartPhone:
 def answer(self):
 print(“Swipe right to answer the call")
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40. Disclaimer
 This is an educational presentation to enhance the skill of
computer science students.
 This presentation is available for free to computer science
students.
 Some internet images from different URLs are used in this
presentation to simplify technical examples and correlate
examples with the real world.
 We are grateful to owners of these URLs and pictures.

41. Thank You!
RTS Tech.
:rtstech30@gmail.com
:+91 8818887087