Python isinstance()

In this tutorial, we will learn about the Python isinstance() function with the help of examples.

The isinstance() function checks if the object (first argument) is an instance or subclass of classinfo class (second argument).

Example

numbers = [1, 2, 3, 4, 2, 5]

# check if numbers is instance of list
result = isinstance(numbers, list)
print(result)

# Output: True

isinstance() Syntax

The syntax of isinstance() is:

isinstance(object, classinfo)

isinstance() Parameters

isinstance() takes two parameters:

object - object to be checked
classinfo - class, type, or tuple of classes and types

isinstance Return Value

isinstance() returns:

True if the object is an instance or subclass of a class or any element of the tuple
False otherwise

If classinfo is not a type or tuple of types, a TypeError exception is raised.

Example 1: How isinstance() works?

class Foo:
  a = 5
  
fooInstance = Foo()

print(isinstance(fooInstance, Foo))
print(isinstance(fooInstance, (list, tuple)))
print(isinstance(fooInstance, (list, tuple, Foo)))

Output

True
False
True

Example 2: Working of isinstance() with Native Types

numbers = [1, 2, 3]

result = isinstance(numbers, list)
print(numbers,'instance of list?', result)

result = isinstance(numbers, dict)
print(numbers,'instance of dict?', result)

result = isinstance(numbers, (dict, list))
print(numbers,'instance of dict or list?', result)

number = 5

result = isinstance(number, list)
print(number,'instance of list?', result)

result = isinstance(number, int)
print(number,'instance of int?', result)

Output

[1, 2, 3] instance of list? True
[1, 2, 3] instance of dict? False
[1, 2, 3] instance of dict or list? True
5 instance of list? False
5 instance of int? True

Also Read: