Classes and Objects

Classes and Objects

Classes:

1. Defining a Class:

• Using the class keyword to define a class.
• Creating a blueprint for objects.

2. Attributes (Properties):

• Defining instance attributes to store data.
• Attributes hold the state of an object.

3. Methods:

• Defining methods to encapsulate behavior.
• Methods define the actions an object can perform.

4. Initializer (__init__):

• Using the __init__ method to initialize attributes during object creation.
• Constructors are called when objects are instantiated.

5. Class and Instance Attributes:

• Differentiating between attributes that belong to the class and instances.
• Class attributes are shared among all instances.

Objects:

1. Creating Objects:

• Instantiating objects from a class.
• Objects are instances of a class.

2. Accessing Attributes:

• Using dot notation to access attributes.
• object.attribute to access instance attributes.

3. Calling Methods:

• Invoking methods on objects.
• object.method() to call a method.

4. Initializer Usage:

• Providing arguments to the __init__ method during object creation.
• Initializing object attributes.

5. Multiple Objects:

• Creating multiple instances of a class.
• Each object maintains its own state.

Using Classes and Objects:

1. Creating and Using Instances:

• Creating instances of a class.
• Setting attributes and calling methods.

2. Modifying Attributes:

• Changing attribute values using methods.
• Encapsulating attribute changes.

3. Encapsulation:

• Using private attributes with a naming convention (e.g., _attribute).
• Encapsulating data for controlled access.

4. Inheritance and Subclasses:

• Creating subclasses that inherit attributes and methods from a superclass.
• Extending and customizing behavior in subclasses.

5. Method Overriding:

• Overriding methods in subclasses to customize behavior.
• Using the super() function to call overridden methods.

6. Using Class and Instance Attributes:

• Understanding the difference between class and instance attributes.
• Accessing class attributes using both class and instance.

Example:

Let's illustrate these concepts with a simple example:

class Dog:
    def __init__(self, name, age):
        self.name = name
        self.age = age
    
    def bark(self):
        print(f"{self.name} says woof!")

# Creating instances of the Dog class
dog1 = Dog("Buddy", 3)
dog2 = Dog("Max", 5)

# Accessing attributes and calling methods
print(f"{dog1.name} is {dog1.age} years old.")
dog1.bark()

print(f"{dog2.name} is {dog2.age} years old.")
dog2.bark()