Python id() Function

Python id() function returns an identity of an object. This is an integer which is guaranteed to be unique. This function takes an argument an object and returns a unique integer number which represents identity. Two objects with non-overlapping lifetimes may have the same id() value.

Signature

Parameters

object : It is an object of which id is to be returned.

Return

It returns a unique integer number.

Let's see some examples of id() function to understand it's functionality.

Python id() Function Example 1

# Python id() function example
# Calling function
val = id("Javatpoint") # string object
val2 = id(1200) # integer object
val3 = id([25,336,95,236,92,3225]) # List object
# Displaying result
print(val)
print(val2)
print(val3)

Output:

139963782059696
139963805666864
139963781994504

Python id() Function Example 2

# Python id() function example
class Student:
    def __init__(self, id, name):
        self.id = id
        self.name = name
        
student = Student(101,"Mohan")        
print(student.id)
print(student.name)
# Calling function
val = id(student) # student class object
# Displaying result
print("Object id:",val)

Output:

101
Mohan
Object id: 140157155861392

Python id() Function Example 3

# Python id() function example
l1 = [1,2,3,4]
l2 = [1,2,3,4]
l3 = [3,5,6,7]
# Calling function
id1 = id(l1)
id2 = id(l2)
id3 = id(l3)
# Displaying result
print((l1==l2),(l1==l3))
# Objects with the same values can have different ids
print((id1==id2),(id1==id3))
# l1 and l2 returns True, while id1 and id2 returns False

Output: