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 listtest_list = [[1, 2, 1], [1, 2, 3], [2, 2, 2, 2], [0]]# printing original listprint("The original list of lists : " + str(test_list))# using list comprehension# convert list of lists to list of setsres = [set(ele) for ele in test_list]# print resultprint("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}]
Time Complexity: O(n)
Auxiliary Space: O(n)
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 listtest_list = [[1, 2, 1], [1, 2, 3], [2, 2, 2, 2], [0]]# printing original listprint("The original list of lists : " + str(test_list))# using map() + setres = list(map(set, test_list))# print resultprint("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}]
Time complexity: O(n), where n is the length of the test_list. The map() + set takes O(n) time
Auxiliary Space: O(n), extra space of size n is required
Method 3: Using a loop and a set constructor
In this method, it creates a list of lists lst_of_lsts and then converts each sublist to a set using a for loop. The resulting sets are stored in a new list called lst_of_sets, and then the contents of the lst_of_sets are printed to the console.
Python3
lst_of_lsts = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]lst_of_sets = []for lst in lst_of_lsts: lst_of_sets.append(set(lst))print(lst_of_sets) |
[{1, 2, 3}, {4, 5, 6}, {8, 9, 7}]
Time complexity: O(n), where n is the length of the lst_of_lsts.
Auxiliary Space: O(n), extra space of size n is required
Method 4: Using a loop and a list constructor
This method iterates through each element of the input list test_list using a for loop. For each element, it creates a set using the set() constructor and appends it to a result list res using the append() method. Finally, it prints the result.
Python3
# initializing listtest_list = [[1, 2, 1], [1, 2, 3], [2, 2, 2, 2], [0]]# printing original listprint("The original list of lists : " + str(test_list))# using a loop and a list constructor# convert list of lists to list of setsres = []for ele in test_list: res.append(set(ele))# print resultprint("The converted list of sets : " + str(res)) |
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}]
Time complexity: O(nm), where n is the length of the input list and m is the maximum length of any sublist in the input list.
Auxiliary space: O(nm), since we create a new set for each sublist in the input list.
