Python – Convert List of lists to list of Sets

Given a list containing lists, the task is to write a Python Program to convert it to a list containing sets.

Examples:

Input : [[1, 2, 1], [1, 2, 3], [2, 2, 2, 2], [0]]
Output : [{1, 2}, {1, 2, 3}, {2}, {0}]

Input : [[4, 4], [5, 5, 5], [1, 2, 3]]
Output : [{4}, {5}, {1, 2, 3}]

Method 1: Using list comprehension

This can easily be achieved using list comprehension. We just iterate through each list converting the lists to the sets.

Python3

# python3 program to convert list
# of lists to a list of sets


# initializing list
test_list = [[1, 2, 1], [1, 2, 3], [2, 2, 2, 2], [0]]

# printing original list
print("The original list of lists : " + str(test_list))

# using list comprehension
# convert list of lists to list of sets
res = [set(ele) for ele in test_list]

# print result
print("The converted list of sets : " + str(res))

Output:

he original list of lists : [[1, 2, 1], [1, 2, 3], [2, 2, 2, 2], [0]]
The converted list of sets : [{1, 2}, {1, 2, 3}, {2}, {0}]

Method 2 : Using map() + set

We can use the combination of map function and set operator to perform this particular task. The map function binds each list and converts it into the set.

Python3

# Python3 code to demonstrate
# convert list of lists to list of sets
# using map() + set

# initializing list
test_list = [[1, 2, 1], [1, 2, 3], [2, 2, 2, 2], [0]]

# printing original list
print("The original list of lists : " + str(test_list))

# using map() + set
res = list(map(set, test_list))

# print result
print("The converted list of sets : " + str(res))

Output:

The original list of lists : [[1, 2, 1], [1, 2, 3], [2, 2, 2, 2], [0]]
The converted list of sets : [{1, 2}, {1, 2, 3}, {2}, {0}]