set of n objects, and show k-element subsets in python

Question

Suppose you have a set of n objects, and you want to list its k-element subsets (that is, its subsets with exactly m elements) solved by Recursive functions without using list(itertools.combinations) for example k_subsets({1,2,3},2 ) show the

[{1, 2}, {1, 3}, {2, 3}]

I know the algorithem, algorithm combinations inputs S, a set of n objects m, the number of objects you’d like to pick from S, with m n outputs the subsets of S of size n do if jSj = m let result = fSg else let result = ; for s 2 S let U = Sns add combinations(U, m) to result return result Scott Hunter — Amin Amin, Jun 02 '20 at 15:19
What exactly is your question? It seems you forgot to write the second half. Your first sentence starts with "suppose you want to do this and that", but then it just stops. — mkrieger1, Jun 02 '20 at 16:00

Ali Hassan Ahmed Khan · Accepted Answer · 2020-06-06T13:28:24.840

0

This will be the code of combination using recursion, and this will give you all the subsets of given list and the subsets of desired length.

l1 = [1, 2, 3]
s = 2
unique = []
def combination(set):
    if set == []:
        return [[]]

    sub = combination(set[1:])
    # This will give you all the subsets of given list and This is also the return variable of the function.
    all_combination = (sub + [[set[0]] + x for x in sub])
    ########################################################
    # This for loop will give you a subsets of desire length.
    for i in range(len(all_combination)):
        if int(len(all_combination[i])) == s and all_combination[i] not in unique:
            unique.append(all_combination[i])
    #########################################################
    return all_combination

print(combination(l1))
print(unique)

edited Jun 06 '20 at 13:28

answered Jun 02 '20 at 18:35

Ali Hassan Ahmed Khan

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Fine, answer is true but not a exact answer of my questions. I want the code that just appear these '[{1, 2}, {1, 3}, {2, 3}]' not all. Just because we work with subset not ordered pair. For example [{1,1}] is not acceptable because we used 1 once or {1,2} and {2,1} is the same. – Amin Amin Jun 06 '20 at 06:12
@AminAmin now check i have updated my answer. This is according to your desire. – Ali Hassan Ahmed Khan Jun 06 '20 at 13:29

set of n objects, and show k-element subsets in python

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