Python hasattr() function is an inbuilt utility function, which is used to check if an object has the given named attribute and return true if present, else false. In this article, we will see how to check if an object has an attribute in Python.
Syntax of hasattr() function
Syntax : hasattr(obj, key)
Parameters :
- obj : The object whose which attribute has to be checked.
- key : Attribute which needs to be checked.
Returns : Returns True, if attribute is present else returns False.
Example 1: Python hasattr() function example
Here we will check if an object has an attribute, to find attributes of the object in python we have demonstrated the following code.
Python3
# declaring classclass GfG: name = "Lazyroar" age = 24# initializing objectobj = GfG()# using hasattr() to check nameprint("Does name exist ? " + str(hasattr(obj, 'name')))# using hasattr() to check mottoprint("Does motto exist ? " + str(hasattr(obj, 'motto'))) |
Output:
Does name exist ? True Does motto exist ? False
Example 2: Performance analysis between hasattr() method and try statement
This is the Simple Ways to Check if an Object has Attribute in Python or not using performance analysis between hasattr() function and try statement.
Python3
import time# declaring classclass GfG: name = "Lazyroar" age = 24# initializing objectobj = GfG()# use of hasattr to check mottostart_hasattr = time.time()if(hasattr(obj, 'motto')): print("Motto is there")else: print("No Motto")print("Time to execute hasattr : " + str(time.time() - start_hasattr))# use of try/except to check mottostart_try = time.time()try: print(obj.motto) print("Motto is there")except AttributeError: print("No Motto")print("Time to execute try : " + str(time.time() - start_try)) |
Output:
No Motto Time to execute hasattr : 5.245208740234375e-06 No Motto Time to execute try : 2.6226043701171875e-06
Result: Conventional try/except takes lesser time than hasattr(), but for readability of code, hasattr() is always a better choice.
Applications: This function can be used to check keys to avoid unnecessary errors in case of accessing absent keys. Chaining of hasattr() is used sometimes to avoid entry of one associated attribute if the other is not present.
