Oop1

• Object-oriented programming


  Refers to the languages that uses objects in programming, which can contain data, in the form of fields, and code, in the form of procedures
• Fields


  • Can be thought of as containers for storing information that is used by the object or class
  • Also known as a data member or member variable
• Principles of programming


  • Data abstraction
  • Encapsulation
  • Inheritance
  • Polymorphism
  • Dynamic bonding
  • Message passing
• Programming languages that uses OOP

  • Java
  • C++
  • Python
• Aim of OOP


  • Aims to implement real-world entities in programming
  • To bind together the data and the functions that operate on them so that no other part of the code can access this data except that function
• Real-World entities


  Is an entity with a physical location (within the universe)
• Name all Real-world entities or OOP Concepts

  • Class
  • Objects
  • Data Abstraction
  • Encapsulation
  • Inheritance
  • Polymorphism
  • Dynamic Bonding
  • Message Passing
• Class


  • Is a user-defined data type
  • Is the design or blueprint of any entity, which defines the core properties and functions
• The class has 2 central components

  • Properties
  • Methods
• Class

  Is an abstraction of some entities which contains common set of properties and methods
• Self

  Means the class itself
• Constructor


  To define and initialize the instance variables
• Instance attribute


  Refers to the properties of that particular object like edge of the triangle being 3, while the edge of the square can be 4
• Data Abstraction


  • Is used to hide the internal functionality of the function from the users
  • It is where the users only interact with the basic implementation of the function, but inner working is hidden
• Double underscore (____)


  We can also perform data hiding by adding the double underscore (____) as a prefix to the attribute which is to be hidden
• Encapsulation


  In Python is one of the 4 important concepts to understand. The other three are inheritance, polymorphism, and abstraction
• Methods to Control Access

  • Using Single Underscore
  • Using Double Underscores
  • Using Getter and Setter methods to access private variables
• Using Single Underscore


  A common Python programming convention to identify a private variable is by prefixing it with an underscore
• Using Double Underscores


  • If you want to make class members like methods and variables private, then you should prefix them with double underscores
  • Is useful to define the properties of the class
• Init method


  Will be called whenever we will create an instance of the class
• Objects


  Is a specific instance of a class. It is a thing in a real world. It is a thing that you want to store and process data about
• Entity


  • Another name for an object
  • Is the existence of something considered apart from its properties
• Instance of an object

  Whenever we create a new class in Python and whenever we create a variable, it automatically creates an
• Self-keyword


  Is used as the first parameter to a method
• Self


  Refers to the current object
• Instance variables


  Are declared inside a method using the self-keyword
• Name mangling


  But Python offers some sort of support to the private modifier. This mechanism is called
• Name mangling- In Python, any identifier with __Var is rewritten by a python interpreter as _Classname__Var, and the class name remains as the present class name
• Using Getter and Setter methods to access private variables


  If you want to access and change the private variables, accessor (getter) methods and mutators (setter methods) should be used, as they are part of Class
• What is the need for Encapsulation in Python

  • Encapsulation helps in achieving the well-defined interaction in every application
  • The Object-Oriented concept focuses on the reusability of code in Python. (DRY – Don't Repeat Yourself)
  • The applications can be securely maintained
  • It ensures the flexibility of the code through a proper code organization
  • It promotes a smooth experience for the users without exposing any back-end complexities
  • It improves the readability of the code. Any changes in one part of the code will not disturb another
  • Encapsulation ensures data protection and avoids the access of data accidentally. The protected data can be accessed with the methods discussed above
  • Encapsulation in Python is, the data is hidden outside the object definition. It enables developers to develop user-friendly experience. This is also helpful in securing data from breaches, as the code is highly secured and cannot be accessed by outside sources
• Inheritance


  • Is an important pillar of OOP
  • The capability of a class to derive properties and characteristics from another class is called
• Inheritance allows the user to reuse the code whenever possible and reduce its redundancy
• Types of Inheritance


  • Single Inheritance
  • Multiple Inheritance
  • Multilevel Inheritance
  • Hierarchical Inheritance
  • Hybrid Inheritance
• Single Inheritance


  Is a type of inheritance where a derived/child class inherits properties and behaviors from a single parent/base class
• Multiple Inheritance


  • Have 2 parent classes and from that 2-parent classes it inherits a single child class and that child class will consist the properties
  • All of the properties of the parent classes will be inherited by the child class using an object
• Python inheritance


  The property of acquiring all the properties and behaviors of the parent object by an object is termed as
• Python facilitates inheritance of a derived class from its base class as well as inheritance of a derived class from another derived class
• Multilevel inheritance in Python


  The inheritance of a derived class from another derived class is called
• Hierarchical Inheritance


  Is the inheritance with 1 parent class which will be inherited for many child classes
• Hybrid inheritance


  Is a mixture of all inheritance