Fist thing,
What is Decorators?
In Python, a decorators is a special type of function that modifies or enhances the behaviour of another function or method without changing its actual code.
Here is an analogy:-
Imagine you have a gift, let say a book. To make it special you wrap up with gift paper. Just like decorators.
Here is the problem when I change the model name of our car attribute it get change but it shouldn't be happened:-
class Car:
total_car=0
def __init__(self,brand,model):
self.brand=brand
self.model=model
Car.total_car+=1
def full_function(self):
return f"{self.brand} {self.model}"
def fuel_type(self):
return "Petrol or Desiel"
@staticmethod
def general_description():
return "Cars mean of transportation"
class ElectricCar(Car):
def __init__(self,brand,model,battery_size):
super().__init__(brand,model)
self.battery_size=battery_size
def fuel_type(self):
return "Electric Charge"
Tata=Car("TATA","Sedan")
Mahindera=Car("Mahindera","Geep")
Tata.model="city"
print(Tata.model)
Output:
city
As you can see I can change model name how avoid this situation and make model read-only.
We are going to use property method. What property method going to do is that having control over attribute so nobody can have access of it.
class Car:
total_car=0
def __init__(self,brand,model):
self.brand=brand
self.__model=model
Car.total_car+=1
def full_function(self):
return f"{self.brand} {self.__model}"
def fuel_type(self):
return "Petrol or Desiel"
@staticmethod
def general_description():
return "Cars mean of transportation"
@property
def model(self):
return self.__model
class ElectricCar(Car):
def __init__(self,brand,model,battery_size):
super().__init__(brand,model)
self.battery_size=battery_size
def fuel_type(self):
return "Electric Charge"
Tata=Car("TATA","Sedan")
Mahindera=Car("Mahindera","Geep")
Tata.model="city"
print(Tata.model)
Output:
ERROR!
Traceback (most recent call last):
File "", line 26, in
File "", line 5, in __init__
AttributeError: property 'model' of 'Car' object has no setter
- You need private the model attribute.
- Use property method to have access of an attribute so nobody can modify it.
- It also says you cannot even modify with function (model()).
- After erasing Tata.model="city" then only you can have access to it.