OOP_Python_01 .pptx

OOP_Python_01 .pptx

• 1.
  AN OVERVIEW OF PYTHON 1
• 2.
  WHAT IS OOP? 🞆OOPis a powerful way to approach the task of programming. 🞆OOP encourages developers to decompose a problem into its constituent parts. 🞆Each component becomes a self-contained object that contains its own instructions and data that relate to that object. 🞆So, complexity is reduced and the programmer can manage larger programs. 2
• 3.
  WHAT IS OOP?(CONT.) 🞆All OOP languages, including Python, share three common defining traits: ⚫Encapsulation 🞆Binds together code and data ⚫Polymorphism 🞆Allows one interface, multiple methods ⚫Inheritance 🞆Provides hierarchical classification 🞆Permits reuse of common code and data 3
• 4.
  PYTHON CONSOLE I/O(OUTPUT) print("Hello, World!") name = "Alice" print("Hello,", name) # Output: # Hello, World! # Hello, Alice 4
• 5.
  PYTHON CONSOLE I/O(OUTPUT) Formatted String: age = 30 print(f"Name: {name}, Age: {age}") # Output: Name: Alice, Age: 30 5
• 6.
  CONSOLE I/O (INPUT) print("Enteryour name:") name = input() print(f"You entered: {name}") user_input = input("Enter your name: ") print("You entered:", user_input) 6
• 7.
  CONSOLE I/O (INPUT) IntegerInput: age_str = input("Enter your age: ") age_int = int(age_str) print(f"Next year you will be {age_int + 1}.") 7
• 8.
  PYTHON COMMENTS ❏Multi-line comments """ Thistext is a string literal that acts as a comment because it is not assigned to a variable. """ ❏Single line comments # This entire line is a comment 8
• 9.
  CLASSES: A FIRSTLOOK 🞆General syntax - 9 class class-name: // private and public variables // private and public functions
• 10.
  CLASSES: A FIRSTLOOK (CONT.) 🞆A class declaration is a logical abstraction that defines a new type. 🞆It determines what an object of that type will look like. 🞆An object declaration creates a physical entity of that type. 🞆That is, an object occupies memory space, but a type definition does not. 10
• 11.
  CLASSES: A FIRSTLOOK (CONT.) 🞆Each object of a class has its own copy of every variable declared within the class (except static variables which will be introduced later), but they all share the same copy of member functions. ⚫ How do member functions know on which object they have to work on? 🞆The answer will be clear when “self” pointer is introduced 11
• 12.
  POLYMORPHISM 🞆Polymorphism refers tofunctions with the same name that can be executed on many objects or classes. 🞆Runtime Polymorphism: ➔ Functions execution of same name is decided in runtime. 🞆Compile-time Polymorphism: ➔ Functions execution of same name is decided in compile time. 12
• 13.
  POLYMORPHISM 🞆Runtime Polymorphism: ➔ Functionoverriding 🞆Compile-time Polymorphism: ➔ Function overloading ➔ Python does not support compile time polymorphism 13
• 14.
  INTRODUCING CLASSES 14
• 15.
  CONSTRUCTORS 🞆Every object wecreate will require some sort of initialization. 🞆A class’s constructor is automatically called by the compiler each time an object of that class is created. 🞆A constructor function has the same name as the class and has no return type in most of OOP languages. 🞆There is no explicit way to call the constructor. 15
• 16.
  CONSTRUCTORS 🞆Python is alittle different 🞆it has a constructor and an initializer. 🞆The constructor function is rarely used. 🞆constructor (__new__) creates the object instance 🞆while the initializer (__init__) sets the initial state or attributes of that newly created object. 16
• 17.
  DESTRUCTORS 🞆The complement ofa constructor is the destructor. 🞆This function is automatically called by the compiler when an object is destroyed. 🞆The name of a destructor is the name of its class, preceded by a ~ in most of the OOP languages. 🞆There is explicit way to call the destructor but highly discouraged. 17
• 18.
  DESTRUCTORS 🞆In Python, thedestructor is a special method named __del__() that is called just before an object is destroyed or garbage-collected 🞆Unlike in languages like C++, destructors are not frequently needed in Python because its automatic garbage collector handles memory management. 18
• 19.
  CONSTRUCTORS THAT TAKE PARAMETERS 🞆InPython we will generally use initializer to initialize the object. 🞆Initializer can be without any parameters 🞆And Initializer can take parameter as well. 19
• 20.
  OBJECT POINTERS 🞆In Python,self is a parameter that acts as a reference to the current instance of a class 🞆In C++, 'this' pointer is an implicit pointer available inside all non-static member function 20
• 21.
  INHERITANCE ❏ Inheritance isa core principle where a new class (subclass/child) acquires properties (attributes) and behaviors (methods) from an existing class ( superclass/parent). 21
• 22.
  TYPES OF INHERITANCEIN PYTHON ❏ Single Inheritance: A child class inherits from only one parent class. ❏ Multiple Inheritance: A class can inherit from more than one parent class. ❏ Multilevel Inheritance: A chain of inheritance where a class inherits from a derived class, creating a grandparent -parent-child relationship. 22