What is the difference between a class variable and a class method in Python?
Davide S

In Python, class variables and class methods are both features of class-level definitions, but they serve different purposes and have distinct characteristics. 1. Class Variable: A class variable is a variable that is shared among all instances of a class. It is defined within the class but outside any instance methods. Class variables are accessible through the class itself or any of its instances. Here's an example of a class variable in Python:

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class MyClass:
    class_variable = 10

    def __init__(self, instance_variable):
   self.instance_variable = instance_variable

# Accessing class variable
print(MyClass.class_variable)  # Output: 10

# Creating instances
obj1 = MyClass(20)
obj2 = MyClass(30)

# Accessing class variable through instances
print(obj1.class_variable)  # Output: 10
print(obj2.class_variable)  # Output: 10

In the above code,class_variable is a class variable defined within theMyClass class. It is accessed using the class name (MyClass.class_variable) or through instances of the class (obj1.class_variable,obj2.class_variable). Class variables are shared among all instances, meaning that modifying the value of a class variable through any instance affects the value accessed through other instances or the class itself. 2. Class Method: A class method is a method that is bound to the class and not the instances. It is defined within the class using the@classmethod decorator and is typically used to perform operations that are related to the class as a whole, rather than specific to individual instances. Here's an example of a class method in Python:

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class MyClass:
    class_variable = 10

    @classmethod
    def class_method(cls):
   return cls.class_variable * 2

# Invoking class method
result = MyClass.class_method()
print(result)  # Output: 20

In the above code,class_method is a class method defined using the@classmethod decorator. Class methods receive the class itself as the first argument (conventionally namedcls) rather than the instance (self). They can access class variables, perform operations related to the class, or modify class-level attributes. Unlike instance methods, class methods do not have access to the individual instance's attributes, but they have access to class-level attributes, including class variables. Class methods are typically used to define methods that operate on or affect the class as a whole. To summarize, the key differences between a class variable and a class method in Python are: - Class variables are shared among all instances of a class, whereas class methods operate on the class itself and are not tied to specific instances. - Class variables store data that is shared across instances, while class methods define operations related to the class as a whole. - Class variables are accessed using the class name or through instances, whereas class methods are invoked using the class name. - Class variables are defined without any specific decorator, while class methods are defined using the@classmethod decorator. Understanding the distinction between class variables and class methods helps in organizing and managing data and behavior at the class level, providing flexibility and control over class-wide operations and shared data.

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