Difference between attributes and properties in Python
Class Attribute: Class Attributes are unique to each class. Each instance of the class will have this attribute.
Example:
# declare a class
class Employee:
# class attribute
count = 0
# define a method
def increase(self):
Employee.count += 1
# create an Employee
# class object
a1 = Employee()
# calling object's method
a1.increase()
# print value of class attribute
print(a1.count)
a2 = Employee()
a2.increase()
print(a2.count)
print(Employee.count)
Output:
1 2 2
In the above example, count variable is a class attribute.
Instance Attribute: Instance Attributes are unique to each instance, (an instance is another name for an object). Every object/instance has its own attribute and can be changed without affecting other instances.
Example:
# create a class
class Employee:
# constructor
def __init__(self):
# instance attribute
self.name = 'Gfg'
self.salary = 4000
# define a method
def show(self):
print(self.name)
print(self.salary)
# create an object of
# Employee class
x = Employee()
# method calling
x.show()
Output:
Gfg 4000
Now, Let's see an example on properties:
1) Create Properties of a class using property() function:
Syntax: property(fget, fset, fdel, doc)
Example:
# create a class
class gfg:
# constructor
def __init__(self, value):
self._value = value
# getting the values
def getter(self):
print('Getting value')
return self._value
# setting the values
def setter(self, value):
print('Setting value to ' + value)
self._value = value
# deleting the values
def deleter(self):
print('Deleting value')
del self._value
# create a properties
value = property(getter, setter, deleter, )
# create a gfg class object
x = gfg('Happy Coding!')
print(x.value)
x.value = 'Hey Coder!'
# deleting the value
del x.value
Output:
Getting value Happy Coding! Setting value to Hey Coder! Deleting value
2) Create Properties of a class Using @property decorator:
We can apply the property function by using @property decorator. This is one of the built-in decorators. A decorator is simply a function that takes another function as an argument and adding to its behavior by wrapping it.
Example:
# create a class
class byDeco:
# constructor
def __init__(self, value):
self._value = value
# getting the values
@property
def value(self):
print('Getting value')
return self._value
# setting the values
@value.setter
def value(self, value):
print('Setting value to ' + value)
self._value = value
# deleting the values
@value.deleter
def value(self):
print('Deleting value')
del self._value
# create an object of class
x = byDeco('happy Coding')
print(x.value)
x.value = 'Hey Coder!'
# deleting the value
del x.value
Output:
Getting value happy Coding Setting value to Hey Coder! Deleting value
Table of difference between Attribute V/s Property
Attribute | Property |
|---|---|
| Attributes are described by data variables for example like name, age, height etc. | Properties are special kind of attributes. |
|
Two types of attributes:
| It has getter, setter and delete methods like __get__, __set__ and __delete__ methods. |
| Class attributes are defined in the class body parts usually at the top. | We can define getters, setters, and delete methods with the property() function. |
| Instance attribute are defined in the class body using self keyword usually it the __init__() method. | If we just want to the read property, there is also a @property decorator which you can add above your method. |
