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como-usar-objetos-python

What are and how to use objects in Python

Object-Oriented Programming is a programming paradigm based on the concept of “objects”.

These are groupings that represent real-world entities with their own characteristics (attributes) and behaviors (methods).

In OOP, objects interact with each other through messages, which allows for a more natural modeling of complex systems.

If you want to learn more about object-oriented programming, here is the link to the Object-Oriented Programming Course.

Definition of a Class in Python

In Python, classes are defined with the keyword class followed by the class name and a colon (:).

A class is a template or a “mold” for creating objects. It defines the properties and behaviors that the objects created from it will have.

class Persona:
    def __init__(self, nombre, edad):
        self.nombre = nombre
        self.edad = edad

    def saludar(self):
        print(f"Hola, mi nombre es {self.nombre} y tengo {self.edad} años.")

  • The __init__ method is a special method called “constructor,” which is automatically executed when creating a new object of the class. Here, we initialize the nombre and edad attributes.

  • The saludar method is an instance method that displays a greeting with the person’s name and age.

Attributes are variables that belong to an object and represent its characteristics or properties *(they can be of any data type (such as numbers, strings, lists, etc).

In the previous example, nombre and edad are attributes of the persona object.

Methods are functions that belong to an object and can operate on its attributes *(they can perform operations such as modifying attribute values or interacting with other objects).

In the example, saludar is a method of the persona object.

Creating Instances

An instance is each of the “examples” we create from a class. Each instance will have its own values for the attributes defined in the class.

To create an object from a class, simply call the class name followed by parentheses.

For example, once we have the Persona class, we can create instances of this class like this,

luis = Persona("Luis", 30)

In this case, we have created an object luis from the Persona class, with the values “Luis” for the nombre attribute and 30 for the edad attribute.

Accessing Attributes and Methods

To access both the attributes or methods of an instance, we simply use the access operator . on the variable that contains the instance.

For example like this,

luis = Persona("Luis", 30)
ana = Persona("Ana", 25)

luis.edad = 35;  # Change Luis's age to 35
ana.edad = 28;   # Change Ana's age to 28

luis.saludar()  # Output: Hola, mi nombre es Luis y tengo 35 años.
ana.saludar()   # Output: Hola, mi nombre es Ana y tengo 28 años.

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