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)

intersection_update() Parameters

The intersection_update() 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_update()

This method returns None (meaning, absence of a return value). It only updates the set calling the intersection_update() method.

Suppose,

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
  • Cremains unchanged

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)

When you run the program, the output will be:

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

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)

When you run the program, the output will be:

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