Python getattr(): Access Object Attributes Dynamically

The getattr() function retrieves the value of an attribute from an object, even if the attribute name is stored as a string. It’s useful for dynamic programming, working with user-defined objects, and handling attributes flexibly.

Example

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

p = Person("Alice", 30)
print(getattr(p, "name"))  
# Output: Alice

This fetches the attribute value dynamically without using p.name.

Syntax

getattr(object, attribute_name, default_value)

• object → The object to retrieve the attribute from.
• attribute_name → The name of the attribute (as a string).
• default_value (optional) → A value to return if the attribute doesn’t exist.

1. Handling Missing Attributes with a Default Value

Avoid errors by providing a default value.

print(getattr(p, "city", "Unknown"))  
# Output: Unknown

This prevents attribute errors when an attribute is missing.

2. Using getattr() to Access Methods

You can use getattr() to call a method dynamically.

class MathOps:
    def add(self, a, b):
        return a + b

m = MathOps()
method = getattr(m, "add")
print(method(5, 3))  
# Output: 8

This is helpful when you don’t know the method name in advance.

3. Using getattr() with User Input

When handling dynamic attributes, getattr() simplifies access.

attr_name = input("Enter attribute name: ")  # Example: name
print(getattr(p, attr_name, "Not Found"))

Useful in interactive applications where users specify attributes.

4. Checking for Attribute Existence Before Accessing

Combine getattr() with hasattr() to check if an attribute exists.

if hasattr(p, "age"):
    print(getattr(p, "age"))

This prevents errors from missing attributes.

Key Notes

• ✔ Access attributes dynamically without using . notation.
• ✔ Avoid errors by using a default value if the attribute is missing.
• ✔ Retrieve methods and call them dynamically.
• ✔ Works great in dynamic and user-driven applications.

By using getattr(), you can access object attributes flexibly, making it a powerful tool for dynamic programming and object handling. 🚀