Python’s magic method
__getattribute__() implements the built-in
getattr() function that returns the value associated with a given attribute name. If the
__getattribute__() error results in an
AttributeError due to a non-existent attribute, Python will call the
__getattr__() function for resolution.
__getattribute__() method takes precedence over the
We call this a “Dunder Method” for “Double Underscore Method” (also called “magic method”). To get a list of all dunder methods with explanation, check out our dunder cheat sheet article on this blog.
Syntax and Minimal Example
Let’s have a look at an example where you override the
__getattribute__ magic method of a custom class
Person to simply print out the string
'hello world' when calling the
getattr() built-in function.
class Person: def __getattribute__(self, attr_name): print('hello world') alice = Person() getattr(alice, 'age') # hello world
__getattribute__ vs __getattr__
__getattribute__ method is similar to
__getattr__. What’s the difference?
Assume a user wants to access an attribute from a given object like so:
my_obj.__getattribute__(my_attr)is called first. If it yields an
AttributeError, Python will hand it to:
my_obj.__getattr__(my_attr)which is called second.
You can see that the former takes precedence over the latter in the following code snippet that defines both methods—but
__getattribute__() is taken as it doesn’t result in an error.
class Person: def __getattribute__(self, attr_name): print('hello world') def __getattr__(self, attr_name): print('hello universe') alice = Person() getattr(alice, 'age') # hello world
Here’s what would’ve happened in the same scenario when raising an
class Person: def __getattribute__(self, attr_name): raise AttributeError def __getattr__(self, attr_name): print('hello universe') alice = Person() getattr(alice, 'age') # hello universe
Python doesn’t even mention the error but passes the execution flow to the
getattr(object, string) function returns the value of the
object‘s attribute with name
If this doesn’t exist, it returns the value provided as an optional third
If that doesn’t exist either, it raises an
An example is
getattr(porsche, 'speed') which is equivalent to
# Define class with one attribute class Car: def __init__(self, brand, speed): self.brand = brand self.speed = speed # Create object porsche = Car('porsche', 100) tesla = Car('tesla', 110) # Two alternatives to get instance attributes: print(getattr(porsche, 'brand') + " " + str(getattr(porsche, 'speed'))) print(tesla.brand + " " + str(tesla.speed)) # Get an attribute that doesn't exist with default argument: print(getattr(porsche, 'color', 'red'))
porsche 100 tesla 110 red
Where to Go From Here?
Enough theory. Let’s get some practice!
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While working as a researcher in distributed systems, Dr. Christian Mayer found his love for teaching computer science students.
To help students reach higher levels of Python success, he founded the programming education website Finxter.com that has taught exponential skills to millions of coders worldwide. He’s the author of the best-selling programming books Python One-Liners (NoStarch 2020), The Art of Clean Code (NoStarch 2022), and The Book of Dash (NoStarch 2022). Chris also coauthored the Coffee Break Python series of self-published books. He’s a computer science enthusiast, freelancer, and owner of one of the top 10 largest Python blogs worldwide.
His passions are writing, reading, and coding. But his greatest passion is to serve aspiring coders through Finxter and help them to boost their skills. You can join his free email academy here.