Python setattr() usage and example

Python built-in functions

The setattr() function sets the value of the object's attribute.

The syntax of setattr() function is:

setattr(object, name, value)

If you want to get the attribute of an object, please usegetattr().

setattr() parameters

The setattr() function has three parameters:

• object -The object that must be set for the attribute

• name -Attribute name

• value -The value assigned to the attribute

setattr() return value

The setattr() method does not return anything. It returns None.

Example1How setattr() works in Python?

class Person:
　　　　name = 'Adam'
　　　　
p = Person()
print('Before modification:', p.name)
# Set the name to 'John'
setattr(p, 'name', 'John')
print('After modification:', p.name)

Output result

Before modification: Adam
After modification: John

Example2When the attribute is not found in setattr():

If the attribute is not found, setattr() creates a new attribute and assigns a value to it. However, this can only be done if the object implements the __dict__() method.

You can usedir()The function checks all properties of the object.

class Person:
　　　　name = 'Adam'
　　　　
p = Person()
# Set the attribute name to John
setattr(p, 'name', 'John')
print('Name is:', p.name)
# Set an attribute that does not exist in Person
setattr(p, 'age',　23)
print('Age is:', p.age)

Output result

Name is: John
Age is:　23

Python built-in functions