Python Set intersection_update()

The intersection_update() updates the set calling intersection_update() method with the intersection of sets.

The intersection of two or more sets is the set of elements which are common to all sets.

To learn more, visit Python set Intersection.

The syntax of intersection_update() is:

A.intersection_update(*other_sets)

1. intersection_update() Parameters

The intersection_update() method allows an arbitrary number of arguments (sets).

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

2. Return Value from Intersection_update()

This method returns None (meaning it does not have a return value). It only updates the set calling the intersection_update() method.

For example:

result = A.intersection_update(B, C)

When you run the code,

• result will be None
• A will be equal to the intersection of A, B, and C
• B remains unchanged
• C remains unchanged

3. Example 1: How intersection_update() Works?

A = {1, 2, 3, 4}
B = {2, 3, 4, 5}

result = A.intersection_update(B)

print('result =', result)
print('A =', A)
print('B =', B)

Output

result = None
A = {2, 3, 4}
B = {2, 3, 4, 5}

4. Example 2: intersection_update() with Two Parameters

A = {1, 2, 3, 4}
B = {2, 3, 4, 5, 6}
C = {4, 5, 6, 9, 10}

result = C.intersection_update(B, A)

print('result =', result)
print('C =', C)
print('B =', B)
print('A =', A)

Output

result = None
C = {4}
B = {2, 3, 4, 5, 6}
A = {1, 2, 3, 4}