How to Use getattr Function in Python: Syntax and Examples

The getattr function in Python retrieves the value of an attribute from an object by name as a string. It takes the object, the attribute name, and an optional default value to return if the attribute does not exist.

Syntax

The getattr function has this syntax:

• getattr(object, name[, default])

object: The object you want to get an attribute from.

name: A string with the attribute's name.

default (optional): A value to return if the attribute is missing, instead of raising an error.

python

value = getattr(object, 'attribute_name', default_value)

Example

This example shows how to use getattr to get an attribute from a simple object and provide a default if it does not exist.

python

class Car:
    def __init__(self, brand, year):
        self.brand = brand
        self.year = year

my_car = Car('Toyota', 2020)

# Get existing attribute
brand = getattr(my_car, 'brand')
print('Brand:', brand)

# Get missing attribute with default
color = getattr(my_car, 'color', 'Unknown')
print('Color:', color)

Output

Brand: Toyota
Color: Unknown

Common Pitfalls

Common mistakes when using getattr include:

• Not providing a default value and causing an AttributeError if the attribute is missing.
• Passing a non-string as the attribute name, which raises a TypeError.
• Confusing getattr with direct attribute access, which does not allow dynamic attribute names.

Always use a string for the attribute name and consider a default value to avoid errors.

python

class Person:
    def __init__(self):
        self.name = 'Alice'

p = Person()

# Wrong: attribute name is not a string
# age = getattr(p, 123)  # Raises TypeError

# Right: attribute name as string
age = getattr(p, 'age', 30)  # Returns 30 as default
print(age)

Output

30

Quick Reference

Parameter	Description
object	The object to get the attribute from
name	The attribute name as a string
default (optional)	Value returned if attribute is missing

Key Takeaways

Use getattr(object, 'attribute_name', default) to access attributes dynamically by name.

Always pass the attribute name as a string to getattr.

Provide a default value to avoid AttributeError if the attribute does not exist.

getattr allows safe access to attributes when you don't know the attribute name in advance.

Without a default, getattr raises AttributeError if the attribute is missing.