What is the difference between a class method and a class variable in Python?
Antek N

In Python, class methods and class variables are both features of classes that allow for shared behavior and data among all instances of the class. However, they have distinct purposes and behaviors. 1. Class Method: A class method is a method that is bound to the class itself rather than the instances of the class. It is defined using the@classmethod decorator and takes the class as the first parameter, usually denoted ascls. Class methods can be used to perform operations that are related to the class as a whole rather than individual instances. They are typically used for tasks such as creating alternative constructors, modifying class-level data, or performing operations that don't require instance-specific data. Here's an example of a class method:

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class MyClass:
    class_variable = 0

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

    @classmethod
    def class_method(cls, new_value):
   cls.class_variable = new_value

# Usage:
obj1 = MyClass(1)
obj2 = MyClass(2)

print(obj1.class_variable)  # Output: 0
print(obj2.class_variable)  # Output: 0

MyClass.class_method(42)

print(obj1.class_variable)  # Output: 42
print(obj2.class_variable)  # Output: 42

In the above code,class_variable is a class variable shared among all instances of theMyClass class. Theclass_method() is a class method defined using the@classmethod decorator. It takes thecls parameter representing the class itself. The class method can modify the class-level data (class_variable) using thecls parameter. 2. Class Variable: A class variable is a variable that is defined within a class but outside of any methods. It is shared among all instances of the class. Any change made to a class variable will be reflected in all instances of the class. Here's an example of a class variable:

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class MyClass:
    class_variable = 0

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

# Usage:
obj1 = MyClass(1)
obj2 = MyClass(2)

print(obj1.class_variable)  # Output: 0
print(obj2.class_variable)  # Output: 0

MyClass.class_variable = 42

print(obj1.class_variable)  # Output: 42
print(obj2.class_variable)  # Output: 42

In the above code,class_variable is a class variable defined within theMyClass class. It is accessed using theClassName.variable syntax. All instances of the class,obj1 andobj2, share the same value ofclass_variable. Changing the value ofclass_variable usingMyClass.class_variable = 42 affects all instances. To summarize, the key differences between class methods and class variables in Python are: - Class methods are methods bound to the class itself and operate on class-level data, while class variables are variables shared among all instances of the class. - Class methods are defined using the@classmethod decorator and take the class (cls) as the first parameter, while class variables are defined outside of any methods. - Class methods are accessed using theClassName.method() syntax, while class variables are accessed using theClassName.variable syntax. Understanding these differences will help you utilize class methods and class variables effectively in your Python code, allowing you to define shared behavior and data in an organized manner.

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