2 methods to Check if an object has an attribute in Python

Introduction #

Python is all about objects and every object in python has some attributes, be it a method, be it a variable and it becomes very important to check for an appropriate attribute inside of an object while writing complex logic.

But is it even possible to check if a particular object has a desired attribute or not?

Since, you are using Python, versatility is your friend and so the answer is yes, you can check if a desired attribute is present inside of the given object or not.

There are not a much of flexibility available to achieve this output but yes there are methods for the same.

Let’s have a look on the same

Method 1: Using hasattr() method #

Python comes with a very handy method called hasattr() to simplify the task of checking if an attribute is present inside of an object.

You can simply call the inbuilt method hasattr(object,attribute) and Python will automatically check if attribute is present inside of object and would return a Boolean accordingly.

Let’s check out the implementation:

class shiksha:
    pypy = 15.0
    def getPy(self):
        print("Python Shiksha")

if hasattr(shiksha, 'pypy'):
   print("Attribute Found")
else:
   print('Attribute Not Found')

if hasattr(shiksha, 'getpy'):
   print("Attribute Found")
else:
   print('Attribute Not Found')

Output:

Attribute Found
Attribute Not Found

Hurray! We got the desired output, since pypy is an attribute of the shiksha class so, we got true as an output but since getpy is not an attribute of the shiksha class, we got false as expected.

Now, since we are programmers, it is better for us to know a method that doesn’t involve any pre-defined method but some orthodox programming methods.

Let’s check out next classic method.

Method 2: Using try and except block #

As coders, a curiosity towards using classic methods for solving problems must be of a great importance since it teaches us a lot of things.

In order to achieve our desired output as well we will now use a try-except classic method and check for an AttributeError in order to notify our user if an attribute is not present in the object.

Let’s checkout this awesome method.

class shiksha:
    pypy = 15.0
    def getPy():
        print("Python Shiksha")

try:
    shiksha.getPy()
except AttributeError:
    print("No Such Attribute found")

try:
    shiksha.pyPie
except AttributeError:
    print("No Such Attribute found")

Output:

Python Shiksha
No Such Attribute found

This code piece also provided us the desired output.

Shiksha has an attribute of getPy() and therefore the method directly gets called upon but on the other hand Shiksha doesn’t have a pyPIe attribute and thus it resulted in an exception throwing an error message for the user.

Conclusion #

We have finally come to the end of this short yet useful article.

In this article we learnt about different Python methods to Check if an object has an attribute and outputting relevant messages and values to the users.

I am Dibyanshu Mohanty, Undergraduate Engineering Student at VIT, Vellore with a keen interest in Web and App Development

https://python.shiksha/authors/dmohanty/