Join our newsletter for the latest updates.

Python Set intersection()

In this tutorial, we will learn about the Python Set intersection() method with the help of examples.

The intersection() method returns a new set with elements that are common to all sets.

Example

A = {2, 3, 5}
B = {1, 3, 5}

# compute intersection between A and B print(A.intersection(B))
# Output: {3, 5}

Syntax of Set intersection()

The syntax of intersection() in Python is:

A.intersection(*other_sets)

intersection() Parameters

intersection() allows arbitrary number of arguments (sets).

Note: * is not part of the syntax. It is used to indicate that the method allows arbitrary number of arguments.


Return Value from Intersection()

intersection() method returns the intersection of set A with all the sets (passed as argument).

If the argument is not passed to intersection(), it returns a shallow copy of the set (A).


Example 1: Python Set intersection()

A = {2, 3, 5, 4}
B = {2, 5, 100}
C = {2, 3, 8, 9, 10}

print(B.intersection(A))
print(B.intersection(C))
print(A.intersection(C))
print(C.intersection(A, B))

Output

{2, 5}
{2}
{2, 3}
{2}

Working of Set intersection()

The intersection of two or more sets is the set of elements that are common to all sets. For example:

A = {1, 2, 3, 4}
B = {2, 3, 4,  9}
C = {2, 4, 9 10}

Then,
A∩B = B∩A ={2, 3, 4}
A∩C = C∩A ={2, 4}
B∩C = C∩B ={2, 4, 9}

A∩B∩C = {2, 4}
Intersection of Three Sets
Intersection of Three Sets

More Examples

A = {100, 7, 8}
B = {200, 4, 5}
C = {300, 2, 3}
D = {100, 200, 300}

print(A.intersection(D))
print(B.intersection(D))
print(C.intersection(D))
print(A.intersection(B, C, D))

Output

{100}
{200}
{300}
set()

Example 3: Set Intersection Using & operator

You can also find the intersection of sets using & operator.

A = {100, 7, 8}
B = {200, 4, 5}
C = {300, 2, 3, 7}
D = {100, 200, 300}

print(A & C)
print(A & D)

print(A & C & D)
print(A & B & C & D)

Output

{7}
{100}
set()
set()
Did you find this article helpful?