Python is a powerful programming language that has gained immense popularity in recent years. One of the key reasons for its popularity is its object-oriented nature, which allows developers to organize their code into classes and objects. In Python, there are two types of classes: old style and new style. In this article, we will explore the difference between these two types of classes.
Old style classes were the default type of classes in Python 2. They are created by simply defining a class with the keyword "class" followed by the name of the class. For example:
```
class Person:
pass
```
As you can see, there is no explicit mention of the parent class in the definition. This is because old style classes do not support inheritance, which is a fundamental concept in object-oriented programming. Inheritance allows a child class to inherit attributes and methods from its parent class, reducing code repetition and making it easier to maintain and extend the code.
On the other hand, new style classes were introduced in Python 2.2 and became the default type of classes in Python 3. They are created by explicitly mentioning the parent class in the definition using parentheses. For example:
```
class Person(object):
pass
```
Note the addition of "object" within the parentheses. This signifies that the class is inheriting from the built-in object class, making it a new style class. This also means that new style classes support inheritance, along with other advanced features such as descriptors, properties, and static methods.
So, why was there a need for new style classes when old style classes were already functional? The main reason was to improve compatibility with other programming languages. Old style classes did not follow the same rules as other classes in other languages, making it difficult for developers to collaborate and integrate their code with code written in other languages.
Another reason for introducing new style classes was to improve the performance of certain operations such as attribute access and method resolution. In old style classes, these operations were slower due to the way they were implemented. New style classes use a new method resolution order (MRO) algorithm, which makes these operations more efficient.
In addition to these reasons, new style classes also introduced a new way of creating objects using the built-in function "super()". This function allows a child class to access the attributes and methods of its parent class, making it easier to customize and extend the functionality of the parent class.
In conclusion, new style classes in Python have several advantages over old style classes. They support inheritance, have better compatibility with other languages, and offer improved performance for certain operations. However, old style classes are still functional and can be used in legacy code bases. It is important for developers to understand the differences between these two types of classes in order to make informed decisions while writing code in Python.
