Python set union

The Python set union function combines all the items in the original set and the specified set. The syntax of this set union method is 

set.union(set1, set2,…,setN)

Python set union example

In this example, we declared two sets. Next, we are combining those two sets using the Python set union method. 

# Python set union
x = {'a', 'b', 'c', 'd'}
y = {'e', 'f', 'g', 'h'}
 
print('Set Items in x = ', x)
print('Set Items in y = ', y)
 
z = x.union(y)
 
print('Set Items in z = ', z)

set union function output

Set Items in x =  {'c', 'd', 'b', 'a'}
Set Items in y =  {'f', 'h', 'e', 'g'}
Set Items in z =  {'f', 'h', 'd', 'g', 'c', 'b', 'a', 'e'}

The Python sets don’t allow duplicate values inside a set. So, while using the union method to combine the two sets, it removes those duplicate values. If you observe the output, a and c was returned only once (though, they are available in both x and y sets).

TIP: Please refer to the Python set in Python.

x = {'a', 'b', 'c', 'd'}
y = {'a', 'f', 'g', 'c', 'h', 'j', 'k'}
 
print('Set Items in x = ', x)
print('Set Items in y = ', y)
 
z = x.union(y)
 
print('Set Items in z = ', z)

set union output

Set Items in x =  {'b', 'a', 'c', 'd'}
Set Items in y =  {'k', 'j', 'g', 'a', 'c', 'h', 'f'}
Set Items in z =  {'b', 'k', 'a', 'd', 'j', 'g', 'c', 'h', 'f'}

Python union example 2

Let me use three sets with union function. This Python set union example, combines the set time from all the three sets. It first combines items in x and then y and z.

x = {'a', 'b' }
y = {'e', 'f', 'g', 'h'}
z = {'apple', 'cherry', 'kiwi'}
 
print('Set Items in x = ', x)
print('Set Items in y = ', y)
print('Set Items in z = ', z)
 
new_set = x.union(y, z)
 
print('Set Items in new = ', new_set)

set union output

Set Items in x =  {'a', 'b'}
Set Items in y =  {'h', 'g', 'e', 'f'}
Set Items in z =  {'kiwi', 'apple', 'cherry'}
Set Items in new =  {'kiwi', 'g', 'h', 'apple', 'e', 'a', 'f', 'b', 'cherry'}

This set union example shows how to combine numeric and string sets.

x = {'a', 'b' }
y = {10, 20, 30, 40}
 
print('Set Items in x = ', x)
print('Set Items in y = ', y)
 
z = x.union(y)
 
print('Set Items in z = ', z)

union function to combine numeric and string sets output

Set Items in x =  {'b', 'a'}
Set Items in y =  {40, 10, 20, 30}
Set Items in z =  {20, 'b', 40, 10, 30, 'a'}

Here, we declare a numeric set, string set, and a mixed set. Next, we used the set union method to combine them all and returning a new set.

x = {'a', 'b' }
y = {10, 20, 30, 40}
z = {120, 'cherry', 90, 'kiwi'}
 
print('Set Items in x = ', x)
print('Set Items in y = ', y)
print('Set Items in z = ', z)
 
new_set = x.union(y, z)
 
print('Set Items in new = ', new_set)
Python set union method 5