The property() is a built-in function in Python that returns the object of the property class. In other words, it is used to create the property of a class. However, we can optionally provide functions to get, set, or delete the attribute value.

Python property function:

Signature

The signature for the property() function is as shown below.

property(fget=None, fset=None, fdel=None, doc=None)

Parameters and return type

  • This method takes four optional parameters. Here, the fget is a function that gets the attribute value whereas the fset is a function that sets the attribute value. Thereafter, the fdel is a function that deletes the attribute value and the doc is a string containing documentation. The default value is none for all these parameters. Moreover, If arguments are not given, property() method returns a base property attribute that doesn’t contain any get, set or delete methods.
  • However, it returns the property attributes formed by given get, set, and delete functions.

Python Built-in Function property Examples:

Example 1: For example, let us take a class student with an attribute department. Thereafter, we will write three methods to get, set and delete the value of the attribute department. Here, we can see when we get or set a value, it automatically calls the methods of the student class.

# student class
class student:
    def __init__(self, value):
        self._dept = value
   
   # getting the values
    def getdepartment(self):
        print('Getting value')
        return self._dept
 
    # setting the values
    def setdepartment(self, d):
        print('Setting value to ' + d)
        self._dept = d
 
    # deleting the values
    def deldepartment(self):
        print('Deleting value')
        del self._dept
 
    dept = property(getdepartment, setdepartment, deldepartment )
 
 
# creating an instance
x = student('computer')
print(x.dept)

#setting the value 
x.dept = 'IT'
#Deleting  
del x.dept

Output

Getting value
computer
Setting value to IT
Deleting value

Example 2: For example, let us take class marks with attribute sports. Thereafter, we will write three methods to get, set and delete the value of the attribute department. Here, we can see when we get or set a value, and it automatically calls the methods of the marks class.

# marks class
class marks:
    def __init__(self, value):
        self._sports = value
   
   # getting the values
    def getmarks(self):
        print('Getting value')
        return self._sports 
 
    # setting the values
    def setmarks(self, d):
        print('Setting value to ',d)
        self._sports  = d
 
    # deleting the values
    def delmarks(self):
        print('Deleting value')
        del self._sports 
 
    sports = property(getmarks, setmarks, delmarks)
 
# creating an instance
x = marks(80)
print(x.sports)

#setting the value 
x.sports = 85
#Deleting  
del x.sports

Output

Getting value
80
Setting value to  85
Deleting value

Example 3: For example, let us take a class area with an attribute radius. Thereafter, we will write three methods to get, set and delete the value of the attribute department. Here, we can see when we get or set a value, it automatically calls the methods of the area class. Here, we are computing area of a circle from the radius.

# area class
class area:
    def __init__(self, value):
        self._radius= value
   
   # getting the values
    def getradius(self):
        return self._radius
 
    # setting the values
    def setradius(self, d):
        print('Setting value to ', d)
        self._radius = d
 
    # deleting the values
    def delradius(self):
        print('Deleting value')
        del self._radius
 
    radius = property(getradius, setradius, delradius )

# creating an instance
x = area(12.5)
print("Area of circle for radius ",x.radius," is ",(3.14*x.radius*x.radius))

#Changing the radius to 13 and computing area once again
x.radius= 13
print("Area of circle for radius ",x.radius," is ",(3.14*x.radius*x.radius))
#Deleting  
del x.radius

Output

Area of circle for radius  12.5  is  490.625
Setting value to  13
Area of circle for radius  13  is  530.66
Deleting value

Conclusion

The property() function returns a property class object. However, in the presence of parameters, it overwrites the property class method.

References

Happy Learning πŸ™‚

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