getattr()

The built-in getattr() function allows you to retrieve the value of an attribute from an object. If the specified attribute doesn’t exist, it can return a default value if provided. Otherwise, it raises an AttributeError exception:

Python 
>>> class Person:
...     def __init__(self, name, age):
...         self.name = name
...         self.age = age
...

>>> jane = Person("Jane", 25)
>>> getattr(jane, "name")
'Jane'

>>> getattr(jane, "age")
25

>>> getattr(jane, "missing", None)
None

getattr() Signatures

Python 
getattr(object, name)
getattr(object, name, default)

Arguments

Argument Description
object The object whose attribute’s value we need to retrieve.
name A string representing the name of the attribute to retrieve.
default An optional value to return if the attribute doesn’t exist.

Return Value

  • If the attribute exists, getattr() returns the value of the attribute.
  • If the attribute doesn’t exist and a default value is provided, it returns the default value.
  • If the attribute doesn’t exist and no default value is provided, it raises an AttributeError exception.

getattr() Examples

With the name of an existing attribute:

Python 
>>> class Circle:
...     def __init__(self, radius):
...         self.radius = radius
...

>>> circle = Circle(10)
>>> getattr(circle, "radius")
10

With a non-existent attribute and a default value:

Python 
>>> getattr(circle, "diameter", 0)
0

With a non-existent attribute without a default value:

Python 
>>> getattr(circle, "diameter")
Traceback (most recent call last):
  ...
AttributeError: 'Circle' object has no attribute 'diameter'

getattr() Common Use Cases

The most common use cases for the getattr() function include:

  • Accessing object attributes dynamically when attribute names are determined at runtime.
  • Providing a default value for non-existent attributes to avoid exceptions.
  • Accessing methods dynamically to call them later.

getattr() Real-World Example

Let’s consider a situation where you have a list of objects, and you need to retrieve a specific attribute from each object, handling cases where the attribute might be missing by using a default value:

Python 
>>> class Car:
...     def __init__(self, make, model, year):
...         self.make = make
...         self.model = model
...         self.year = year
...

>>> cars = [
...     Car("Toyota", "Corolla", 2020),
...     Car("Ford", "Mustang", 2018),
...     Car("Tesla", "Model S", 2022)
... ]

>>> for car in cars:
...     print(getattr(car, "color", "Unknown"))
...
Unknown
Unknown
Unknown

In this example, getattr() helps retrieve the .color attribute from each Car object, providing a default value of "Unknown" when the attribute isn’t present.

Related Resources

OOP in Python 3

Tutorial

Object-Oriented Programming (OOP) in Python

In this tutorial, you'll learn all about object-oriented programming (OOP) in Python. You'll learn the basics of the OOP paradigm and cover concepts like classes and inheritance. You'll also see how to instantiate an object from a class.

intermediate python

For additional information on related topics, take a look at the following resources:

By Leodanis Pozo Ramos • Updated Nov. 12, 2024 • Reviewed by Dan Bader
Python’s Built-in Functions Share Feedback