Classes and Instances

Python Tutorials - Herong's Tutorial Examples

∟Classes and Instances

This chapter provides introductions and tutorial examples about classes and instances. Topics include introduction of class, instance, attribute and method; using 'class' statement; using __init__() method; differences between class attributes and instance attributes.

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What Is Class

What Is Class Attribute

What Is Class Method

What Is Class Instance

What Is Instance Attribute

Class Attribute vs. Instance Attribute

What Is __init__() Method

What Is Instance Method

Takeaways:

A class is an object of the "type" data type that can store data with executable code, and can instantiate new objects.
A class attribute is a variable hiding inside a class, accessible with the attribute reference expression (class.identifier).
A class method is a function hiding inside a class, callable with the attribute reference expression (class.identifier(...))
A class instance is an object instantiated from a given class using a function call expression, class(...).
An instance attribute is a variable hiding inside an instance, accessible with the attribute reference expression (instance.identifier).
You can access a class attribute using the instance attribute reference expression (instance.identifier).
But there is no way to update a class attribute using the instance attribute reference expression (instance.identifier).
You can call a class method using the instance method call form (instance.identifier(...)), which inserts the instance reference into the argument list as the first argument.