Python Membership and Identity Operators: Understanding the Basics

NISHANT TIWARI 02 Apr, 2024 • 4 min read

Introduction

Unlocking the potential for intuitive and expressive code, operator overloading in Python stands as a cornerstone of flexibility and customizability. It empowers developers to infuse their classes with operator semantics, bridging the gap between abstract concepts and concrete implementations. By reimagining operators such as +, -, *, or and within custom classes, Python transcends conventional programming norms, fostering concise and readable code reminiscent of mathematical expressions. This article sets forth on an expedition through the universe of operator overloading, illuminating its intricacies, benefits, and practical applications spanning many domains in Python programming.

Python Membership

What are Membership and Identity Operators in Python?

Membership operators in Python, namely `in` and not in, test whether a value or variable is found in a sequence like strings, lists, tuples, etc. For example:

Code

# Membership operators example
x = [1, 2, 3, 4, 5]
print(3 in x)
print(6 not in x)

Output

True

True

On the other hand, identity operators in Python, namely `is` and `is not`, compare the memory locations of two objects. For example:

Code

# Identity operators example
a = 10
b = 10
print(a is b)
print(a is not b)

Output

True

False

These operators are useful in various scenarios where we need to check for the presence of an element in a sequence or compare the memory locations of objects.

Membership Operators in Python

Membership Operators in Python allow you to check whether a specific element is present in a sequence. Let’s examine the two main membership operators in Python: `in` and’ not in’.

The `in` Operator

The `in` operator checks if a value exists in a sequence like a list, tuple, string, or dictionary. It returns `True` if the value is found and `False` otherwise.

Code

# Define a list
fruits = ['apple', 'banana', 'cherry']
# Check if 'apple' is in the list
if 'apple' in fruits:
    print('Yes, apple is in the list')

Output

Yes, apple is in the list

The `not in` Operator

Conversely, the `not in` operator checks if a value does not exist in a sequence. It returns `True` if the value is not found and `False` if it is found.

Code

# Define a tuple
numbers = (1, 2, 3, 4, 5)
# Check if 6 is not in the tuple
if 6 not in numbers:
    print('Yes, 6 is not in the tuple')

Output

Yes, 6 is not in the tuple

You can easily check for the presence or absence of elements in Python sequences using the’ in’ and’ not in’ operators. These operators are handy tools for conditional statements and data validation in your Python programs.

Identity Operators in Python

Identity Operators in Python compare the memory locations of two objects.

The `is` operator checks if two variables point to the same object in memory.

Code

list1 = [1, 2, 3]
list2 = [1, 2, 3]
print(list1 is list2)

Output

False

On the other hand, the `is not` operator checks if two variables do not point to the same object in memory.

Let’s modify the previous example to use the `is not` operator:

Code

list1 = [1, 2, 3]
list2 = [1, 2, 3]
print(list1 is not list2)

Output

True

These operators are useful when you want to compare the identity of objects rather than their values.

Differences Between Membership and Identity Operators

Membership operators in Python, such as “in” and “not in,” check if a value exists in a sequence like a list, tuple, or string. On the other hand, identity operators “is” and “is not,” are used to compare the memory locations of two objects.

When using the “in” operator, Python checks if a value is present in a sequence and returns True if it is, otherwise False. Conversely, the “not in” operator returns True if the value is not present in the sequence.

In contrast, the “is” operator checks if two variables point to the same object in memory. If they do, it returns True; otherwise, it returns False. As the name suggests, the “is not” operator returns the opposite.

Practical Examples of Using Membership and Identity Operators

Let’s dive into some practical examples to understand how membership and identity operators work in Python. 

Membership Operators Example

Code

fruits = ['apple', 'banana', 'cherry']
if 'banana' in fruits:
    print('Yes, banana is in the list')

Output

Yes, banana is in the list

Identity Operator Example

Code

x = 5
y = 5
if x is y:
    print('x and y are pointing to the same object')

Object

x and y are pointing to the same object

Conclusion

In summary, membership and identity operators are indispensable assets within the Python arsenal, empowering developers to execute pivotal examinations and contrasts. Whether the task entails validating the existence of an element within a sequence or discerning the equivalence of two variables referencing the same memory object, these operators offer a succinct and potent resolution. Proficiency in their utilization augments the clarity, efficacy, and resilience of Python code and underscores the importance of judicious deployment. As one traverses the programming landscape, harnessing these operators with discernment is imperative, refining the coding workflow and guaranteeing peak application efficiency.

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NISHANT TIWARI 02 Apr 2024

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