CODEWITHSUNDEEP
pythonrecursiongeneratoryield
finite_diffidence
finite_diffidence

Reputation: 943

Convert Recursive Python Generator Function to Non Generator Function

I have the following function in Python, and I want to convert it into a more vanilla function that does not use yield so I can translate it to other languages.

Could someone please explain how I could go about this?

The function simply prints out the permutations of n choose m.

i.e. for n==4, m==2, it will create arrays of the form:

1001, 1100, 1010 and so on.

def bitmasks(n, m):
    if n == m:
        yield (1 << n) - 1
    elif m > 0:
        for x in bitmasks(n-1, m-1):
            yield (1 << (n-1)) + x
        for x in bitmasks(n-1, m):
            yield x
    else:
        yield 0

Upvotes: 0

Views: 66

Answers (2)

Tristan Nemoz
Tristan Nemoz

Reputation: 2048

Add your results to a list.

def bitmasks(n, m):
    if n == m:
        return [(1 << n) - 1]
    elif m > 0:
        res = []
        for x in bitmasks(n-1, m-1):
            res.append((1 << (n-1)) + x)
        for x in bitmasks(n-1, m):
            res.append(x)
        return res
    else:
        return [0]

Upvotes: 2

Pythocrates
Pythocrates

Reputation: 553

The function does not print anything, it just yields each result piece by piece. You can create an empty list in the beginning and then replace each yield by an append to your list. In the end, you just return the full list of results.

Upvotes: 2

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