Python set intersection

The intersection (A∩B) of two sets A and B is the set that contains all the elements common between both the sets.

We can perform an intersection between multiple sets too. Following image shows the set intersection example between two sets and three sets.

Set Intersection

Python set intersection

In Python, we can use set class intersection() function to get the intersection of two sets.

Let’s look at an example of the intersection between two sets.

Copy
set1 = set('abcde')

set2 = set('ae')

print(set1)
print(set2)

# two sets intersection
print(set1.intersection(set2))

Output:

Copy
{'a', 'e', 'b', 'd', 'c'}
{'a', 'e'}
{'a', 'e'}

Python Two Sets Intersection

The intersection() function takes multiple set arguments too. Let’s look at another example of the intersection between multiple sets.

Copy
set1 = set('abcde')
set2 = set('ae')
set3 = {'a'}
print(set1.intersection(set2, set3))

Output: {'a'}

Python Multiple Set Intersection

Set intersection without arguments

We can call intersection() function without an argument too. In this case, a copy of the set will be returned.

Let’s see if the returned copy refers to the same set or a different one.

Copy
set1 = set('ab')
set4 = set1.intersection()
print(set4)

# check if shallow copy or deep copy
set1.add('0')
set1.remove('a')
print(set1)
print(set4)

Output:

Copy
{'b', 'a'}
{'0', 'b'}
{'c', 'b', 'a'}

Reference: Official Documentation

About Pankaj

If you have come this far, it means that you liked what you are reading. Why not reach little more and connect with me directly on Google Plus, Facebook or Twitter. I would love to hear your thoughts and opinions on my articles directly.

Recently I started creating video tutorials too, so do check out my videos on Youtube.