Python Set intersection(): Method and & Operator Examples

A.intersection(B) returns a new set containing elements common to both inputs. The & operator is the set-to-set equivalent. The original sets are not changed.

The method form can accept iterable arguments; operator forms require set-like operands. Use intersection_update() when the original set should be reduced in place. See the Set operations overview.

Set order: sets are unordered. Whenever an example prints a set, the displayed element order can differ between runs or Python environments.

On this page

Video Tutorial on Set
intersection using & operator
Using type()
Using intersection() method
Using More Than Two Sets
intersection() method
intersection_update()

Video Tutorial on Set

intersection using & operator

All distinct elements from both sets
Using ampersand ( & ) operator

A={1,2,3}
B={3,4,5}
print(A & B)

Output ( Note 3 is the only common element )

{3}

Using type()

We can check the output by using type()

A={1,2,3}
B={3,4,5}
x=A & B 
print(type(x))

Output

<class 'set'>

Using intersection() method

A={'a','b','c'}
B={'a','y','z'}
print(A.intersection(B))

Output

{'a'}

Using More Than Two Sets

We can use any number of sets with intersection()

A={'a','b','c'}
B={'a','y','z'}
C={'a','k','l'}
print(A & B & C)

Output

{'a'}

intersection() method

Using string ( iterable object ) with intersection() method

A={'a','b','c','x','y'}
B='Alex'
print(A.intersection(B))

Output

{'x'}

Note : we can't use iterable object by using ampersand ( & ), the intersection operator

Using list with intersection() method.

A={'a','b','c'}
B=['a','x','y']
print(A.intersection(B))

Output

{'a'}

Below code will generate error.

print(A & B)

 TypeError: unsupported operand type(s) for &: 'set' and 'list'

intersection_update()

In all above code by using intersection() we created a new set. By using intersection_update() method we can change the original set with common elements.
All Set Methods Set Operations Questions with solutions on set
union() difference() symmetric_difference()

tuple set Dictionary Python- Tutorials

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

About the author Watch on YouTube

Connect: