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Union() function in Python

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Python set Union() Method returns a new set which contains all the items from the original set.

Union of two given sets is the set which contains all the elements of both the sets. The union of two given sets A and B is a set which consists of all the elements of A and all the elements of B such that no element is repeated.

Image

 

The symbol for denoting union of sets is ‘U’

Python set Union() Method Syntax:

Syntax: set1.union(set2, set3, set4….)

Parameters: zero or more sets

Return: Returns a set, which has the union of all sets(set1, set2, set3…) with set1. It returns a copy of set1 only if no parameter is passed.

Python set Union() Method Example:

Python3




A = {2, 4, 5, 6}
B = {4, 6, 7, 8}
 
print("A U B:", A.union(B))

Output:

A U B: {2, 4, 5, 6, 7, 8}

Example 1: Working with Python set Union() methods

Python3




set1 = {2, 4, 5, 6}
set2 = {4, 6, 7, 8}
set3 = {7, 8, 9, 10}
 
# union of two sets
print("set1 U set2 : ", set1.union(set2))
 
# union of three sets
print("set1 U set2 U set3 :", set1.union(set2, set3))

Output

set1 U set2 :  {2, 4, 5, 6, 7, 8}
set1 U set2 U set3 : {2, 4, 5, 6, 7, 8, 9, 10}

Output: 

set1 U set2 :  {2, 4, 5, 6, 7, 8}
set1 U set2 U set3 : {2, 4, 5, 6, 7, 8, 9, 10}

Example 2: Python Set Union Using the | Operator

We can use “|” operator to find the union of the sets.

Python3




set1 = {2, 4, 5, 6}
set2 = {4, 6, 7, 8}
set3 = {7, 8, 9, 10}
 
# union of two sets
print("set1 U set2 : ", set1 | set2)
 
# union of three sets
print("set1 U set2 U set3 :", set1 |set2 | set3)

Output

set1 U set2 :  {2, 4, 5, 6, 7, 8}
set1 U set2 U set3 : {2, 4, 5, 6, 7, 8, 9, 10}

Output:

set1 U set2 :  {2, 4, 5, 6, 7, 8}
set1 U set2 U set3 : {2, 4, 5, 6, 7, 8, 9, 10}

Example 3 : Python Set Union() Method on String

Python3




A = {'ab', 'ba', 'cd', 'dz'}
B = {'cd', 'ab', 'dd', 'za'}
 
print("A U B:", A.union(B))

Output

A U B: {'za', 'ab', 'dd', 'dz', 'ba', 'cd'}

Example 4 : Python Set Union() Method on multiple set (With 3 Set).

Python3




A = {2, 4, 5, 6}
B = {4, 6, 7, 8}
c = {7, 8, 9, 0}
 
print("A U B:", A.union(B).union(c))


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Last Updated : 19 Sep, 2022
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