What are object-oriented programming (OOP) languages?

Did you know that everything is an object?

In object-oriented programming (OOP) languages, humans, animals, plants, and places are all objects!

Is the concept of objects in computer programming familiar to you?

No worries, using Python, you'll find out how objects can play an important role to help with the development and implementation of complex programs. 🔥

Object-oriented programming (OOP) is a computer programming model that focuses on objects to organize the code and maximize reusability.

In OOP, a program is formed by objects that interact with the user, and other objects and programs.

Some of the main benefits of object-oriented programming are:

Modularity

• The code for a program is divided into different parts.

• Every part is independent.

• Modularity helps programmers with troubleshooting and collaborative development.

Reusability

• The code can be easily reused. There is no need to code the same functionality repeatedly.

• Reusing code avoids errors when creating code.

Productivity

• Programmers can build programs faster using standard libraries and reusable code.

• Programmers can collaborate and work in different modules of the program at the same time.

Security

• Programmers can protect a specific part of the code so it's not accessible from any other part of the program.

Object-oriented programming is ultimately about taking a huge problem and breaking it down to solvable chunks.

— Robert Half, software developer

Some examples of areas where object-oriented programming is used are:

Artificial Intelligence (AI) expert systems

• OOP is used to power AI expert systems' fundamental characteristics: being reliable and highly responsive, and offering high performance.

Office Automation Systems

• OOP is used to automatize communication and sharing information tasks within an organization saving time and effort.

• Automatized tasks such as managing emails, word processing, and web calendars.

Simulation and Modeling Systems

• These systems imitate real-world products and systems and are considered very complex.

• They're used in medicine and other natural sciences.

• OOP can help to simplify complex modelling systems.

Real-Time Systems

• These systems carry complex functions in specific time constraints.

• Examples of real-time systems are flight control systems and real-time monitors.

• Code developed with object-oriented technology is adaptable, easy to modify, and reusable, which helps address these systems' complexities.

Python, Java, C++, and JavaScript are programming languages that implement OOP principles.

Test Your Knowledge ⚡

Meet Juan. He's trying to decide to learn about object-oriented programming (OOP) to become a software developer. Juan should learn about OOP because:

A. OOP helps programmers be more productive because they can reuse code and libraries.

B. OOP is used in important areas of work such as artificial intelligence and real-time systems.

C. OOP is a secure way of developing software.

D. OOP helps with problem-solving because you can break down a problem into smaller pieces.

Using Python, you can explore in action four important OOP characteristics with the example of a "Student":

To hear an audio explanation of the above image, press play on the audio player below:

Having the class Student:

• you can create as many objects, students, as you want,

• you will not need to rewrite any code to do so, and

• the information of each student will be contained inside the object.

How is OOP implemented in Python for the example in the picture?

1. Classes

• Classes are the templates or blueprints of objects.

• In Python, you can start coding the class Student with:

  

2. Attributes

• Attributes are defined in the class and describe the state of the object.

• For the class Student, some attributes can be the name, the student ID, and the courses the student is taking. In the example, you can code it in this way:

  

3. Methods

• Methods are defined in the class.

• They describe what the object "can do."

• To obtain the courses a student is taking, you can use the following code in Python:

  

4. Objects

• An object has the attributes and methods defined in the class.

• The attributes in an object have specific values.

• To create the object for a student named Alissa with a student ID and a list of her courses, use this line of code:

  

What if you want to create a specific kind of student? For instance, a college student. Do you need to start from scratch to create a new class?

No! It's simpler. You can create the class CollegeStudent using the class Student, and modify this class to add more attributes and methods:

To hear an audio explanation of the above image, press play on the audio player below:

The way the classes Student and CollegeStudent are created is possible thanks to 4 key OOP principles:

1. Inheritance

• A class can inherit the methods and attributes from another class, the parent class, to become a child class.

• This helps to reuse code and simplifies development.

• In Python, you can start creating the class CollegeStudent with:

  

2. Encapsulation

• Information about the object is hidden.

• It's up to the programmer to decide what attributes can be accessed from outside the object. This helps with the safety of the program.

• For a Student object, it helps to protect the student's information.

3. Abstraction

• Implementation of the object is hidden.

• Complex code is hidden. The code inside the methods isn't visible outside the object.

• Abstraction helps the security of the code.

4. Polymorphism

• Polymorphism means “many shapes”. In OOP, methods in a child class can work differently from the ones in the parent class.

• This helps to change and specialize the methods inherited from a parent class.

• In the class CollegeStudent, the method "find_courses" could return the number of courses instead of their names:

  

Do you feel excited about what you've learned?

Test Your Knowledge ⚡

Juan's been learning Python to implement OOP principles. He is now studying to apply for an internship as a junior programmer in a tech company. One question Juan found while studying is: Which of these are characteristics of object-oriented programming in Python?

A. Methods inherited in child classes can't be modified.

B. Child classes are created using the format "class ChildClass(ParentClass):".

C. Classes are the blueprints for objects.

D. You cannot create objects, only classes.

Do you want to be part of the object-oriented programming community?