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Learn Object-Oriented Programming in Python

Declaring a Class in Python

Discover how to declare a class in Python by using the class keyword, following proper naming conventions, and creating class objects. This lesson helps you understand the basics of Python class structures and object instantiation to kickstart your object-oriented programming skills.

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Declaration #

In Python, classes are defined as follows:

Python 3.5
class ClassName:
    pass

The class keyword tells the compiler that we are creating a custom class, which is followed by the class name and the : sign.

All the properties and methods of the class will be defined within the class scope.

Naming rules

The following rules must be adhered to when naming classes:

  1. Must start with a letter or underscore
  2. Should only be comprised of numbers, letters, or underscores

Creating a class object

The name of the class, MyClass, will be used to instantiate an object of the class in our main program. We can create an object of a class by simply using the name of the class followed by a pair of parenthesis. It looks similar to calling a function, but Python can distinguish between the two and creates a new object of the corresponding class. An example of this is given below:

Python 3.5
class MyClass:
    pass
obj = MyClass()  # creating a MyClass Object
print(obj)

Well done! You’ve created your first object-oriented program in Python. Printing this object, obj, will show the memory address at which this object is stored.

This is just a basic implementation of a Python class and doesn’t serve any particular purpose as it does not contain any properties or methods.