Class Method in Python

 

Class Method

To define static method, @classmethod decorator is used, method defined under @classmethod decorator are class method.

 #program to define class method

 class Employee_data :
  @classmethod
  def operation(cls):
      print("this is a class method")

• Class Method take "cls" as a default parameter.

 #program

 class Employee_data :
  @classmethod
  def operation(cls):
   cls.a = 10
   cls.b = 20
   return (cls.a + cls.b)
 

• Class Method perform operation on Class variables.

 #program

 class Employee_data :
  @classmethod
  def operation(cls):
   cls.a = 10
   cls.b = 20
   return (cls.a + cls.b)

  @classmethod
  def display_operation(cls):
   print(cls.operation())

• Class name can be called by class name and object as well.

 #program

 class Employee_data :
  @classmethod
  def operation(cls):
   cls.a = 10
   cls.b = 20
   return (cls.a + cls.b)

  @classmethod
  def display_operation(cls):
   print("return is :", cls.operation())

 todo = Employee_data()
 todo.display_operation()             # calling based on object name

 Employee_data.display_operation()    # calling based on class name

 #Output

 return is : 30
 return is : 30

• Class Method gets memory at class loading time.

 #program 

 class Employee_data :
  @classmethod
  def operation(cls):
   cls.a = 10
   cls.b = 20
   return (cls.a + cls.b)

  @classmethod
  def display_operation(cls):
   print("return is :", cls.operation())

 Employee_data.display_operation()    # calling based on class name before creating object

 todo = Employee_data()
 todo.display_operation()             # calling based on object name

 #Output

 return is : 30
 return is : 30

• Class Method perform operation on Static variables as well.

 #program

 class Employee_data :

  website = "AETies"

  @classmethod
  def operation(cls):
   cls.a = 10
   cls.b = 20
   return (cls.a + cls.b)

  @classmethod
  def display_operation(cls):
   print("return is :", cls.operation())
   print("website is :", cls.website)   #calling static variable

 Employee_data.display_operation()    # calling based on class name before creating object

 todo = Employee_data()
 todo.display_operation()             # calling based on object name

 #Output

 return is : 30
 website is : AETies
 return is : 30
 website is : AETies