Lecture 23:- Identity Comparison Operators in Python

In Python, identity comparison operators are used to compare the identity of two objects. These operators check whether two variables or expressions refer to the same memory location (i.e., the same object) rather than comparing their values. There are two identity comparison operators in Python:

1. is operator: The is operator returns True if two variables or expressions point to the same object, and False otherwise.

Example:

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x = [1, 2, 3] y = x z = [1, 2, 3] print(x is y)  # Output: True (x and y refer to the same list object) print(x is z)  # Output: False (x and z refer to different list objects)

In this example, x and y are two variables that both refer to the same list object, so x is y returns True. On the other hand, x and z refer to two different list objects with the same values, so x is z returns False.

1. is not operator: The is not operator is the negation of the is operator. It returns True if two variables or expressions point to different objects, and False if they point to the same object.

Example:

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x = [1, 2, 3] y = x z = [1, 2, 3] print(x is not y)  # Output: False (x and y refer to the same list object) print(x is not z)  # Output: True (x and z refer to different list objects)

In this example, x and y refer to the same list object, so x is not y returns False. However, x and z refer to two different list objects with the same values, so x is not z returns True.

Identity comparison is different from value comparison (done using == operator). While == checks if the values of two variables are equal, is checks if the variables themselves point to the same object in memory. Be cautious when using is and is not for mutable objects like lists, as their contents can change, affecting the results of identity comparison. For most cases, you will use == for value comparison and is for identity comparison with immutable objects like numbers, strings, and tuples.