Python – Find union of multiple sets
Given multiple sets list, the task is to write a Python program to find union of each set.
Examples:
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Input : test_list = [{4, 3, 5, 2}, {8, 4, 7, 2}, {1, 2, 3, 4}, {9, 5, 3, 7}]
Output : {1, 2, 3, 4, 5, 7, 8, 9}
Explanation : All elements from all sets included. Duplicates removed.
Input : test_list = [{4, 3, 5, 2}, {8, 4, 7, 2}, {1, 2, 3, 4}]
Output : {1, 2, 3, 4, 5, 7, 8}
Explanation : All elements from all sets included. Duplicates removed.
Method #1 : Using union() + * operator
In this, we perform task of getting union using union(), and * operator is used to perform task of packing all the sets together.
Python3
# Python3 code to demonstrate working of# Union multiple sets# Using union() + * operator # initializing listtest_list = [{4, 3, 5, 2}, {8, 4, 7, 2}, {1, 2, 3, 4}, {9, 5, 3, 7}] # printing original listprint("The original list is : " + str(test_list)) # * operator packs sets for unionres = set().union(*test_list) # printing resultprint("Multiple set union : " + str(res)) |
Output:
The original list is : [{2, 3, 4, 5}, {8, 2, 4, 7}, {1, 2, 3, 4}, {9, 3, 5, 7}]
Multiple set union : {1, 2, 3, 4, 5, 7, 8, 9}
Method #2 : Using chain.from_iterable() + * operator
In this, we perform task of union, which in turn is flattening using from_iterable().
Python3
# Python3 code to demonstrate working of# Union multiple sets# Using chain.from_iterable() + * operatorfrom itertools import chain # initializing listtest_list = [{4, 3, 5, 2}, {8, 4, 7, 2}, {1, 2, 3, 4}, {9, 5, 3, 7}] # printing original listprint("The original list is : " + str(test_list)) # * operator packs sets for unionres = set(chain(*test_list)) # printing resultprint("Multiple set union : " + str(res)) |
Output:
The original list is : [{2, 3, 4, 5}, {8, 2, 4, 7}, {1, 2, 3, 4}, {9, 3, 5, 7}]
Multiple set union : {1, 2, 3, 4, 5, 7, 8, 9}
