Python hasattr(): Check if an Object Has an Attribute

The hasattr() function checks if an object has a specific attribute. It returns True if the attribute exists, otherwise False. This is useful for avoiding errors, checking object properties dynamically, and handling flexible data structures.

Example

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

p = Person("Alice")

print(hasattr(p, "name"))  
# Output: True
print(hasattr(p, "age"))  
# Output: False

This prevents errors from accessing missing attributes.

Syntax

hasattr(object, attribute_name)

• object → The object to check.
• attribute_name → The name of the attribute (as a string).
• Returns → True if the attribute exists, otherwise False.

1. Using hasattr() Before Accessing an Attribute

Avoid AttributeError when working with unknown objects.

if hasattr(p, "name"):
    print(p.name)  
else:
    print("Attribute not found.")

Useful when working with dynamic data.

2. Checking Methods in a Class

You can also check if an object has a specific method.

class Car:
    def drive(self):
        return "Driving"

car = Car()

print(hasattr(car, "drive"))  
# Output: True
print(hasattr(car, "brake"))  
# Output: False

Great for handling objects flexibly in larger applications.

3. Using hasattr() with Dictionaries

When working with objects that act like dictionaries, hasattr() can be useful.

class Config:
    def __init__(self, **kwargs):
        self.__dict__.update(kwargs)

settings = Config(debug=True, theme="dark")

print(hasattr(settings, "debug"))  
# Output: True
print(hasattr(settings, "mode"))  
# Output: False

Perfect for storing dynamic settings or configurations.

4. Using hasattr() to Validate User Input

Before accessing user-provided attributes, check if they exist.

user_input = "age"
if hasattr(p, user_input):
    print(getattr(p, user_input))
else:
    print("Invalid attribute.")

Avoids crashes from invalid input.

Key Notes

• ✔ Checks if an object has a specific attribute.
• ✔ Prevents AttributeError by validating before access.
• ✔ Works with both instance variables and methods.
• ✔ Useful for dynamic configurations, user input, and debugging.

By using hasattr(), you can handle objects more safely and dynamically, making your code robust and flexible. 🚀