Python Set intersection_update() Method

The intersection_update() method updates a set in place by keeping only the elements that are common to all specified sets or iterables.

Syntax

set.intersection_update(*others)

Parameters

others: One or more sets (or other iterables like tuples or lists) to find common elements with.

Return Value

Doesn’t return anything. It modifies the set in place.

Examples

Example 1: Intersection update of two sets

a = {1, 2, 3, 4}
b = {3, 4, 5, 6}

a.intersection_update(b)
print(a) # Output: {3, 4}

Example 2: Intersection update with multiple sets

You can pass multiple sets, separated by commas, as arguments to the intersection_update() method.

a = {1, 2, 3, 4}
b = {3, 4, 5, 6}
c = {3, 4, 8, 9}

a.intersection_update(b, c)
print(a) # Output: {3, 4}

Example 3: Intersection update with different iterable types

You can also pass iterables of different types, such as lists or tuples, as arguments to the intersection_update() method.

a = {1, 2, 3, 4}
b = [3, 4, 5, 6] # a list
c = (3, 4, 8, 9) # a tuple

a.intersection_update(b, c)
print(a) # Output: {3, 4}

The &= Operator

The &= operator is the shorthand for performing a set intersection update.

For example:

a = {1, 2, 3, 4}
b = {3, 4, 5, 6} 
 
a &= b
print(a) # Output: {3, 4}

Multiple set intersection

a = {1, 2, 3, 4}
b = {3, 4, 5, 6} 
c = {3, 4, 8, 9} 

a &= b & c
print(a) # Output: {3, 4}