Given a list, the task is to write a Python program to perform all possible replacements from other lists to the current list.
Input : test_list = [4, 1, 5], repl_list = [8, 10]
Output : [(4, 1, 5), (4, 1, 8), (4, 1, 10), (4, 5, 8), (4, 5, 10), (4, 8, 10), (1, 5, 8), (1, 5, 10), (1, 8, 10), (5, 8, 10)]
Explanation : All elements are replaced by 0 or more elements from 2nd list
Input : test_list = [4, 1], repl_list = [8, 10]
Output : [(4, 1), (4, 8), (4, 10), (1, 8), (1, 10), (8, 10)]
Explanation : All elements are replaced by 0 or more elements from 2nd list
Method #1 : Using combinations() + len()
In this, we perform the task of constructing combinations of the merged lists using combinations() and len() is used to restrict the size of output to the length of the initial list.
Python3
# Python3 code to demonstrate working of# All replacement combination from other list# Using combinations() + len()from itertools import combinations# initializing listtest_list = [4, 1, 5]# printing original listprint("The original list is : " + str(test_list))# initializing replacement listrepl_list = [8, 10]# using combinations() to get all combinations replacementsres = list(combinations(test_list + repl_list, len(test_list)))# printing resultprint("All combinations replacements from other list : " + str(res)) |
Output:
The original list is : [4, 1, 5] All combinations replacements from other list : [(4, 1, 5), (4, 1, 8), (4, 1, 10), (4, 5, 8), (4, 5, 10), (4, 8, 10), (1, 5, 8), (1, 5, 10), (1, 8, 10), (5, 8, 10)]
Time Complexity: O(n)
Auxiliary Space: O(1)
Method #2 : Using combinations() + extend()
In this, we perform the task of concatenating the list using extend(), rest all the functionalities is similar to the above method.
Python3
# Python3 code to demonstrate working of # All replacement combination from other list# Using combinations() + extend()from itertools import combinations# initializing listtest_list = [4, 1, 5]# printing original listprint("The original list is : " + str(test_list))# initializing replacement list repl_list = [8, 10]# using combinations() to get all combinations replacements# extend() for concatenationn = len(test_list)test_list.extend(repl_list)res = list(combinations(test_list, n))# printing result print("All combinations replacements from other list : " + str(res)) |
Output:
The original list is : [4, 1, 5] All combinations replacements from other list : [(4, 1, 5), (4, 1, 8), (4, 1, 10), (4, 5, 8), (4, 5, 10), (4, 8, 10), (1, 5, 8), (1, 5, 10), (1, 8, 10), (5, 8, 10)]
Time Complexity: O(n), where n is the number of elements in the list “test_list”.
Auxiliary Space: O(n), where n is the number of elements in the list “test_list”.
