What is the purpose of the isinstance() function in Python OOP?

a) To check if an object is an instance of a specific class or a tuple of classes

b) To create an instance of a class

c) To compare two objects

d) To initialize an object’s attributes

Answer:

a) To check if an object is an instance of a specific class or a tuple of classes

Explanation:

The isinstance() function in Python is used to check if an object is an instance of a specific class or a tuple of classes. It returns True if the object is an instance of the specified class or classes, and False otherwise. This function is useful for type-checking and ensuring that objects passed to functions or methods are of the expected type.

class Animal:
    pass

class Dog(Animal):
    pass

# Checking instances
dog = Dog()
print(isinstance(dog, Dog))     # Output: True
print(isinstance(dog, Animal))  # Output: True
print(isinstance(dog, list))    # Output: False

In this example, the isinstance() function checks whether the dog object is an instance of the Dog class, the Animal class (its parent), and the list class. The results reflect the inheritance relationship and class types.

Using isinstance() is important for writing flexible and error-resistant code, as it allows you to verify that objects are of the correct type before performing operations on them.