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Practice

Checking if an Object is an Instance of a Class

How can you determine if a particular object is an instance of a specific class?

This can be done using the built-in isinstance() function.


How to Use isinstance()​

The isinstance() function is used as follows:

How to Use isinstance()
isinstance(object, class)

This function returns a value based on the following conditions:

  • It returns True if the object is an instance of the specified class, or an instance of a subclass that inherits from the specified class.

  • It returns False otherwise.


Examples of Using isinstance()​

Below is an example of checking if my_dog, an instance of the Dog class, is an instance of various classes:

Example of Using isinstance()
class Animal:
    pass

class Fish:
    pass

class Dog(Animal):
    pass

my_dog = Dog()

print(isinstance(my_dog, Dog))
# True
print(isinstance(my_dog, Animal))
# True
print(isinstance(my_dog, Fish))
# False
print(isinstance(my_dog, object))
# True
print(isinstance(my_dog, int))
# False

In the code above, the my_dog object is an instance of the Dog class, so isinstance(my_dog, Dog) returns True.

Additionally, since the Dog class inherits from the Animal class, isinstance(my_dog, Animal) also returns True.

However, my_dog is not an instance of the Fish class, so isinstance(my_dog, Fish) returns False.

Lastly, since the object class is the parent class of all classes, isinstance(my_dog, object) returns True.

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