Methods and Attributes

Now that you know what a class is and how to create objects, it’s time to delve into two key concepts: attributes and methods. These are the fundamental components that give functionality and characteristics to your objects.

What are Attributes?

Attributes are variables that store information about the state of an object. Each object can have different values for its attributes.

class Person:
def __init__(self, name, age):
self.name = name
self.age = age

p1 = Person('Ana', 30)
print(p1.name)  # Ana
print(p1.age)    # 30

In this example, name and age are attributes of each Person object.

What are Methods?

Methods are functions defined within a class that describe the behaviors of objects. They always receive at least one parameter: self, which represents the object itself.

class Person:
def __init__(self, name):
self.name = name

def greet(self):
print(f'Hello, I am {self.name}!')

p1 = Person('Ana')
p1.greet()  # Hello, I am Ana!

Types of Attributes

Instance attributes: Are unique to each object (like self.name).
Class attributes: Are shared by all instances of the class.

class Pet:
species = 'Dog'  # Class attribute

def __init__(self, name):
self.name = name  # Instance attribute

m1 = Pet('Rex')
m2 = Pet('Luna')
print(m1.species)  # Dog
print(m2.species)  # Dog

Types of Methods

Instance methods: Use self and operate on the object.
Class methods: Use @classmethod and receive cls as the first parameter.
Static methods: Use @staticmethod and receive neither self nor cls.

class Calculator:
@staticmethod
def add(a, b):
return a + b

@classmethod
def description(cls):
return 'Simple calculator'

print(Calculator.add(3, 4))         # 7
print(Calculator.description())        # Simple calculator

Best Practices

Use descriptive names for attributes and methods.
Private attributes (for internal use only) are named with an underscore: _attribute.
Document your methods using docstrings.

Summary

Attributes: store object information.
Methods: define object behaviors.
There are instance, class, and static attributes and methods.
Mastering these concepts allows you to create more useful and flexible classes.

Ready to continue? Try creating a class with your own attributes and methods!