Python Set intersection() Method

The intersection() method in Python is used to find the common elements between two or more sets. It returns a new set containing elements that are present in all the specified sets. This method is useful for identifying shared elements across multiple sets.

Table of Contents

1. Introduction
2. intersection() Method Syntax
3. Understanding intersection()
4. Examples
   • Basic Usage
   • Intersection of Multiple Sets
5. Real-World Use Case
6. Conclusion

Introduction

The intersection() method is a built-in set method in Python that allows you to compute the intersection of two or more sets. The intersection of sets is a set containing all elements that are common to all the sets involved in the operation.

intersection() Method Syntax

The syntax for the intersection() method is as follows:

set.intersection(*others)

Parameters:

• others: One or more sets to compare against.

Returns:

• A new set containing elements that are common to all the specified sets.

Understanding intersection()

The intersection() method returns a new set containing elements that are common to the original set and all the other specified sets. If no other sets are specified, it returns a shallow copy of the original set.

Examples

Basic Usage

To demonstrate the basic usage of intersection(), we will find the intersection of two sets.

Example

# Creating two sets
set1 = {1, 2, 3, 4, 5}
set2 = {4, 5, 6, 7, 8}

# Finding the intersection of set1 and set2
intersection_set = set1.intersection(set2)
print("Intersection of set1 and set2:", intersection_set)

Output:

Intersection of set1 and set2: {4, 5}

Intersection of Multiple Sets

This example shows how to find the intersection of multiple sets.

Example

# Creating three sets
set1 = {1, 2, 3, 4, 5}
set2 = {4, 5, 6, 7, 8}
set3 = {3, 4, 5, 9, 10}

# Finding the intersection of set1, set2, and set3
intersection_set = set1.intersection(set2, set3)
print("Intersection of set1, set2, and set3:", intersection_set)

Output:

Intersection of set1, set2, and set3: {4, 5}

Real-World Use Case

Identifying Common Customers

In real-world applications, the intersection() method can be used to identify common customers who are present in multiple customer lists.

Example

# Sets of customers for different products
product_a_customers = {"Alice", "Bob", "Charlie", "David"}
product_b_customers = {"Charlie", "David", "Eve", "Frank"}
product_c_customers = {"Charlie", "David", "George", "Helen"}

# Finding common customers who bought all products
common_customers = product_a_customers.intersection(product_b_customers, product_c_customers)
print("Common customers:", common_customers)

Output:

Common customers: {'David', 'Charlie'}

Finding Shared Interests

The intersection() method can also be used to find shared interests among groups of people.

Example

# Sets of interests for different people
alice_interests = {"reading", "music", "hiking"}
bob_interests = {"music", "hiking", "coding"}
charlie_interests = {"music", "hiking", "photography"}

# Finding shared interests among Alice, Bob, and Charlie
shared_interests = alice_interests.intersection(bob_interests, charlie_interests)
print("Shared interests:", shared_interests)

Output:

Shared interests: {'music', 'hiking'}

Conclusion

The intersection() method in Python is used for finding common elements between two or more sets. By using this method, you can efficiently identify shared items across multiple sets, making it particularly helpful in scenarios such as identifying common customers, finding shared interests, and managing collections of items in your Python applications.