Instance Method in Python

 

Instance Method

To define instance method, no decorator is used.

 #program to define instance class

 class Employee_data :
     def operations(self):
         print("this is instance method")

• Instance Method take "self " as default parameter. 

 # program to define instance class

 class Employee_data:
   def operations(self):
      self.a = 10
      self.b = 20
      print("result : ", self.a + self.b)

• Instance Method gets memory at object creation time.

 #program

 class Employee_data:
   def operations(self):
      self.a = 10
      self.b = 20
      print("result : ", self.a + self.b)

 Employee_data.operations()            # calling by class name before creating object

 my_data = Employee_data()
 my_data.operations()

 #Output

 Traceback (most recent call last):
   File "C:/Self_Practice_Er_M_S_Dandyan/Python/Pycharm/xml/main.py", line 9, in <module>
     Employee_data.operations()
 TypeError: operations() missing 1 required positional argument: 'self'

• Object is used to access instance method.

 #program 

 class Employee_data:
   def operations(self):
      self.a = 10
      self.b = 20
      print("result : ", self.a + self.b)

 my_data = Employee_data()
 my_data.operations()

 #output

 result :  30

• Instance Method will perform operation on instance variables.

 #program

 class Employee_data:
   def operations(self):
      self.a = 10
      self.b = 20

   def disply_operation(self):
      self.operations()
      print("a :", self.a)
      print("b :", self.b)
      print("a + b :", self.a + self.b)

 my_data = Employee_data()
 my_data.disply_operation()

 #Output

 a : 10
 b : 20
 a + b : 30

• Instance Method can perform operation on "cls" and static variables 

 #program

 class Employee_data:

   website = "AETies"

   @classmethod
   def class_operation(cls):
      cls.a = 10

   def operations(self):
      self.b = 20

   def disply_operation(self):

      self.class_operation()
      self.operations()
      print("website", Employee_data.website)
      print("a :", self.a)
      print("b :", self.b)
      print("a + b :", self.a + self.b)

 my_data = Employee_data()
 my_data.disply_operation()

 #Output

 website AETies
 a : 10
 b : 20
 a + b : 30