How Do Static Variables and Methods Work in Python?

Creating Static Variables and Methods in Python

In Python, static variables and methods are referred to as class variables and class methods, respectively. These entities are defined at the class level and can be accessed and manipulated without instantiating objects.

Class Variables

Class variables are declared within the class definition, outside any method. They are shared among all instances of the class and can be accessed using the class name followed by a dot. For example:

class MyClass:
    i = 3

print(MyClass.i)  # Outputs 3

Class Methods

Class methods are functions that are defined within a class, but unlike instance methods, they operate on the class itself rather than on an instance. They are declared using the @staticmethod decorator.

class MyClass:
    @staticmethod
    def f(arg1, arg2, ...): ...

Class methods can be called directly using the class name, without an object. They are typically used to perform tasks that are independent of individual instances, such as utility functions or type-checking.

Classmethods Over Staticmethods

Some programmers prefer classmethods over staticmethods as they can receive the class type as the first argument. This allows the method to access class-specific information and perform more complex operations.

class MyClass:
    @classmethod
    def g(cls, arg1, arg2, ...): ...

Example

Consider the following class definition with both a class variable and a class method:

class MyClass:
    count = 0

    @classmethod
    def get_count(cls):
        return cls.count

This class contains a class variable count that keeps track of the number of created objects and a class method get_count that retrieves the current value of count. To use these, we can write:

MyClass.count += 1  # Increment the class variable
print(MyClass.get_count())  # Call the class method to get the count

Class variables and methods provide a convenient way to define and use shared data and functionality among different instances of a class, simplifying code organization and improving code reusability.

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