{"id":606,"date":"2020-10-17T08:04:05","date_gmt":"2020-10-17T08:04:05","guid":{"rendered":"https:\/\/www.pythontutorial.net\/?page_id=606"},"modified":"2025-03-27T03:04:33","modified_gmt":"2025-03-27T03:04:33","slug":"python-set-intersection","status":"publish","type":"page","link":"https:\/\/www.pythontutorial.net\/python-basics\/python-set-intersection\/","title":{"rendered":"Python Set Intersection"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you’ll learn about the Python set intersection and how to use it to intersect two or more sets.<\/p>\n\n\n\n

TL;DR #<\/a><\/h2>\n\n\n\n

In Python, you can use the set intersection()<\/code> method or set intersection operator (&) to intersect two or more sets<\/a>:<\/p>\n\n\n

new_set = set1.intersection(set2, set3)\nnew_set = set1 & set2 & set3<\/code><\/span><\/pre>\n\n\n
The intersection() method and & operator have the same performance.<\/p>\n\n\n\n
Introduction to Python set intersection #<\/a><\/h2>\n\n\n\n
When intersecting two or more sets<\/a>, you’ll get a new set consisting of elements that exist in all sets.<\/p>\n\n\n\n
Suppose that you have two following sets s1<\/code> and s2<\/code>:<\/p>\n\n\n
s1 = {'Python'<\/span>, 'Java'<\/span>,'C++'<\/span>}\ns2 = {'C#'<\/span>, 'Java'<\/span>, 'C++'<\/span> }<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
The intersection of these two sets returns a new set that contains two elements 'Java'<\/code> and 'C++'<\/code>:<\/p>\n\n\n
s = {'Java'<\/span>, 'C++'<\/span>}<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
… because they’re the only elements that exist in both sets.<\/p>\n\n\n\n
The following Venn diagram illustrates the intersection of two sets s1<\/code> and s<\/code>2:<\/p>\n\n\n\n
\"Python<\/figure>\n\n\n\n
The set intersection has many useful applications. For example, you can use set intersections to find the common favorites of two friends on a social networking application or to search for common skills of two or more employees on an HR application.<\/p>\n\n\n\n
In Python, you can intersect two or more sets using the set intersection()<\/code> method or set intersection operator (&<\/code>).<\/p>\n\n\n\n
Using Python set intersection() method to intersect two or more sets #<\/a><\/h3>\n\n\n\n
This example shows how to use the set intersection()<\/code> method to intersect two or more sets:<\/p>\n\n\n
new_set = set1.intersection(set2, set3, ...)<\/code><\/span><\/pre>\n\n\n
The following shows how to use the intersection()<\/code> method to intersect the sets s1 and s2:<\/p>\n\n\n
s1 = {'Python'<\/span>, 'Java'<\/span>, 'C++'<\/span>}\ns2 = {'C#'<\/span>, 'Java'<\/span>, 'C++'<\/span>}\n\ns = s1.intersection(s2)\n\nprint<\/span>(s)\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
{'C++'<\/span>, 'Java'<\/span>}<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
Using Python set intersection (&) operator to intersect two or more sets #<\/a><\/h3>\n\n\n\n
Python provides you with the set intersection operator (&<\/code>) that allows you to intersect two or more sets:<\/p>\n\n\n
new_set = s1 & s2 & s3 & ...<\/code><\/span><\/pre>\n\n\n
The following example uses the set intersection operator (&<\/code>) to intersect the sets s1 and s2:<\/p>\n\n\n
s1 = {'Python'<\/span>, 'Java'<\/span>, 'C++'<\/span>}\ns2 = {'C#'<\/span>, 'Java'<\/span>, 'C++'<\/span>}\n\ns = s1 & s2\n\nprint<\/span>(s)<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
{'C++'<\/span>, 'Java'<\/span>}<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
Set intersection() method vs set intersection operator (&) #<\/a><\/h3>\n\n\n\n
The set intersection operator only allows sets, while the set intersection()<\/code> method can accept any iterables<\/a>, like strings<\/a>, lists<\/a>, and dictionaries<\/a>.<\/p>\n\n\n\n
If you pass iterables to the intersection()<\/code> method, it’ll convert the iterables to set before intersecting them.<\/p>\n\n\n\n
However, the set intersection operator (&<\/code>) will raise an error if you use it with iterables.<\/p>\n\n\n\n
The following example uses the intersection()<\/code> method to intersect a set with a list:<\/p>\n\n\n
numbers = {1<\/span>, 2<\/span>, 3<\/span>}\nscores = [2<\/span>, 3<\/span>, 4<\/span>]\n\nnumbers = numbers.intersection(scores)\n\nprint<\/span>(numbers)<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
{2, 3}<\/code><\/span><\/pre>\n\n\n
If you use the set intersection operator (&<\/code>) instead, you’ll get an error:<\/p>\n\n\n
numbers = {1<\/span>, 2<\/span>, 3<\/span>}\nscores = [2<\/span>, 3<\/span>, 4<\/span>]\n\nnumbers = numbers & scores\n\nprint<\/span>(numbers)<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
TypeError<\/span>: unsupported operand type(s) for<\/span> &: 'set'<\/span> and 'list'<\/span><\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
Summary #<\/a><\/h2>\n\n\n\n
Try it<\/a><\/p>\n\n\n\n
Try it<\/a><\/p>\n\n\n\n
Try it<\/a><\/p>\n\n\n\n
Try it<\/a><\/strong><\/p>\n\n\n\n