docs(python): add new chapter on Object-Oriented Programming (OOPs) in Python

Author: codewithdhruba01

docs/python/python-oops.md

@@ -0,0 +1,185 @@
+---
+id: python-oops
+title: Object-Oriented Programming
+sidebar_label: OOPs in Python
+sidebar_position: 11
+tags:
+  [
+    Python,
+    List in Python,
+    Introduction of python,
+    Python Syntax,
+    Variables,
+    Operators,
+    Type Casting,
+    String,
+    Tuple in Python
+    Array in Python
+    Functions in Python
+    Recursion in Python
+  ]
+---
+
+# Object-Oriented Programming (OOPs) in Python
+
+Python is an **object-oriented programming language**, which means it supports concepts like **classes, objects, inheritance, polymorphism, encapsulation, and abstraction**.  
+OOP allows developers to structure programs so that properties and behaviors are bundled into objects, making code **modular, reusable, and easier to maintain**.
+
+---
+
+## 🔹 What is OOP?
+
+- **Object-Oriented Programming (OOP)** is a programming paradigm based on the concept of **objects**.  
+- Each object can hold **data (attributes)** and **functions (methods)** that operate on that data.  
+
+ **Benefits of OOP in Python:**
+- Reusability of code
+- Encapsulation of data
+- Modularity and abstraction
+- Easier debugging and maintenance
+
+---
+
+## 🔹 Classes and Objects
+
+A **class** is a blueprint for creating objects.  
+An **object** is an instance of a class.  
+
+```python
+# Defining a class
+class Person:
+    def __init__(self, name, age):
+        self.name = name
+        self.age = age
+
+    def greet(self):
+        return f"Hello, my name is {self.name} and I am {self.age} years old."
+
+# Creating objects
+p1 = Person("Alice", 25)
+p2 = Person("Bob", 30)
+
+print(p1.greet())  # Output: Hello, my name is Alice and I am 25 years old.
+print(p2.greet())  # Output: Hello, my name is Bob and I am 30 years old.
+````
+
+
+
+## 🔹 Attributes and Methods
+
+* **Attributes** → Variables inside a class.
+* **Methods** → Functions defined inside a class.
+
+````python
+class Car:
+    wheels = 4  # Class attribute
+
+    def __init__(self, brand, model):
+        self.brand = brand   # Instance attribute
+        self.model = model
+
+    def info(self):         # Instance method
+        return f"{self.brand} {self.model} has {Car.wheels} wheels."
+
+c1 = Car("Tesla", "Model S")
+print(c1.info())  # Tesla Model S has 4 wheels.
+````
+
+## 🔹 Encapsulation
+
+Encapsulation means **restricting access** to certain variables/methods.
+In Python, we use:
+
+* `_protected_var` → convention for protected members
+* `__private_var` → name mangling for private members
+
+````python
+class BankAccount:
+    def __init__(self, balance):
+        self.__balance = balance   # Private variable
+
+    def deposit(self, amount):
+        self.__balance += amount
+
+    def get_balance(self):
+        return self.__balance
+
+acc = BankAccount(1000)
+acc.deposit(500)
+print(acc.get_balance())   # 1500
+````
+
+---
+
+## 🔹 Inheritance
+
+Inheritance allows a class (child) to acquire properties of another class (parent).
+
+````python
+# Base class
+class Animal:
+    def speak(self):
+        return "This is an animal."
+
+# Derived class
+class Dog(Animal):
+    def speak(self):
+        return "Woof! Woof!"
+
+class Cat(Animal):
+    def speak(self):
+        return "Meow!"
+
+d = Dog()
+c = Cat()
+print(d.speak())  # Woof! Woof!
+print(c.speak())  # Meow!
+````
+
+
+## 🔹 Polymorphism
+
+Polymorphism allows the same method name to perform different tasks depending on the object.
+
+````python
+for animal in [Dog(), Cat()]:
+    print(animal.speak())
+
+# Output:
+# Woof! Woof!
+# Meow!
+````
+
+
+## 🔹 Abstraction
+
+Abstraction means **hiding implementation details** and showing only the necessary functionality.
+In Python, we use the `abc` module to create abstract classes.
+
+````python
+from abc import ABC, abstractmethod
+
+class Shape(ABC):
+    @abstractmethod
+    def area(self):
+        pass
+
+class Circle(Shape):
+    def __init__(self, radius):
+        self.radius = radius
+
+    def area(self):
+        return 3.14 * self.radius * self.radius
+
+c = Circle(5)
+print(c.area())  # 78.5
+````
+
+## 🔹 Summary
+
+* **Class & Object** → Blueprint and instance
+* **Attributes & Methods** → Data and behavior inside a class
+* **Encapsulation** → Restricting access
+* **Inheritance** → Reusing parent class features
+* **Polymorphism** → Same function name, different behavior
+* **Abstraction** → Hiding unnecessary details