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Object-oriented programming (OOP)

It's been quite a long and hopefully nice journey and, by now, we should be ready to explore OOP. I'll use the definition from Kindler, E.; Krivy, I. (2011). Object-oriented simulation of systems with sophisticated control by International Journal of General Systems, and adapt it to Python:

Object-oriented programming (OOP) is a programming paradigm based on the concept of "objects", which are data structures that contain data, in the form of attributes, and code, in the form of functions known as methods. A distinguishing feature of objects is that an object's method can access and often modify the data attributes of the object with which they are associated (objects have a notion of "self"). In OO programming, computer programs are designed by making them out of objects that interact with one another.

Python has full support for this paradigm. Actually, as we have already said, everything in Python is an object, so this shows that OOP is not just supported by Python, but it's a part of its very core.

The two main players in OOP are objects and classes. Classes are used to create objects (objects are instances of the classes from which they were created), so we could see them as instance factories. When objects are created by a class, they inherit the class attributes and methods. They represent concrete items in the program's domain.