Python setattr()

The built-in function setattr() is used to assign the given value to the specified attribute of the specified object.

setattr(object, name, value) #where object indicates whose attribute value is needs to be change

setattr() Parameters:

Takes three parameters. We can say that setattr() is equivalent to object.attribute = value.

setattr() Return Value

The setattr() method doesn't return anything it only assign objects attribute value. This function is useful in dynamic programming in such a situation we cannot assign attribute value using the 'dot' operator.

Examples of setattr() method in Python

class PersonName:
    name = 'Dany'
    
p = PersonName()
print('Before modification:', p.name)

# setting name to 'John'
setattr(p, 'name', 'John')

print('After modification:', p.name)
 

Output:

Before modification: Dany
After modification: John

class PersonName:
    name = 'Dany'
    
p = PersonName()

# setting attribute name to John
setattr(p, 'name', 'John')
print('Name is:', p.name)

# setting an attribute not present in Person
setattr(p, 'age', 23)
print('Age is:', p.age)
 

Output:

Name is: John
Age is: 23

class PersonName:

    def __init__(self):
        self._name = None

    def get_name(self):
        print('get_name called')
        return self._name

    # for read-only attribute
    name = property(get_name, None)


p = PersonName()

setattr(p, 'name', 'Sayooj')
 

Output:

Traceback (most recent call last):
  File "/Users/sayooj/Documents/github/journaldev/Python-3/basic_examples/python_setattr_example.py", line 39, in 
    setattr(p, 'name', 'Sayooj')
AttributeError: can't set attribute