Given a list with some elements being a list of optional elements. The task is to find all the possible combinations from all options.
Examples:
Input: test_list = [1,2,3]
Output:
[1], [1, 2], [1, 2, 3], [1, 3]
[2], [2, 3], [3]
Example 1: Get all possible combinations of a list’s elements using combinations
Python3
from itertools import combinations# initializing listtest_list = ["GFG", [5, 4], "is", ["best", "good", "better", "average"]]idx=0temp = combinations(test_list, 2)for i in list(temp): idx = idx+1 print ("Combination", idx, ": ", i) |
Output:
Combination 1 : ('GFG', [5, 4])
Combination 2 : ('GFG', 'is')
Combination 3 : ('GFG', ['best', 'good', 'better', 'average'])
Combination 4 : ([5, 4], 'is')
Combination 5 : ([5, 4], ['best', 'good', 'better', 'average'])
Combination 6 : ('is', ['best', 'good', 'better', 'average'])
Example 2: Get all possible combinations of a list’s elements using combinations_with_replacement
Python3
from itertools import combinations_with_replacement# initializing listtest_list = ["GFG", [5, 4], "is", ["best", "good", "better", "average"]]idx=0temp = combinations_with_replacement(test_list, 2)for i in list(temp): idx = idx+1 print ("Combination", idx, ": ", i) |
Output:
Combination 1 : ('GFG', 'GFG')
Combination 2 : ('GFG', [5, 4])
Combination 3 : ('GFG', 'is')
Combination 4 : ('GFG', ['best', 'good', 'better', 'average'])
Combination 5 : ([5, 4], [5, 4])
Combination 6 : ([5, 4], 'is')
Combination 7 : ([5, 4], ['best', 'good', 'better', 'average'])
Combination 8 : ('is', 'is')
Combination 9 : ('is', ['best', 'good', 'better', 'average'])
Combination 10 : (['best', 'good', 'better', 'average'], ['best', 'good', 'better', 'average'])
Example 3: Get all possible combinations of a list’s elements using loop
In this, we use a nested loop to get index wise combinations from each nested option list, and then the outer loop is used to get default values in all combinations.
Python3
def combinations(iterable, r): pool = tuple(iterable) n = len(pool) if r > n: return indx = list(range(r)) yield tuple(pool[i] for i in indx) while True: for i in reversed(range(r)): if indx[i] != i + n - r: break else: return indx[i] += 1 for j in range(i+1, r): indx[j] = indx[j-1] + 1 yield tuple(pool[i] for i in indx)x = [2, 3, 1, 6, 4, 7]for i in combinations(x, 2): print(i) |
Output:
(2, 3) (2, 1) (2, 6) (2, 4) (2, 7) (3, 1) (3, 6) (3, 4) (3, 7) (1, 6) (1, 4) (1, 7) (6, 4) (6, 7) (4, 7)
Example 4: Get all possible combinations of a list’s elements using recursion
Python3
import copydef combinations(target, data): for i in range(len(data)): new_lis = copy.copy(target) new_data = copy.copy(data)# print(new_lis, new_data) new_lis.append(data[i]) new_data = data[i+1:] print(new_lis) combinations(new_lis, new_data)target = []data = [1, 2, 3, 4]combinations(target, data) |
Output:
(2, 3) (2, 1) (2, 6) (2, 4) (2, 7) (3, 1) (3, 6) (3, 4) (3, 7) (1, 6) (1, 4) (1, 7) (6, 4) (6, 7) (4, 7)
