I'm trying to create a powerset in Python 3. I found a reference to the itertools
module, and I've used the powerset code provided on that page. The problem: the code returns a reference to an itertools.chain
object, whereas I want access to the elements in the powerset. My question: how to accomplish this?
Many thanks in advance for your insights.
itertools
functions return iterators, objects that produce results lazily, on demand.
You could either loop over the object with a for
loop, or turn the result into a list by calling list()
on it:
from itertools import chain, combinations
def powerset(iterable):
"powerset([1,2,3]) --> () (1,) (2,) (3,) (1,2) (1,3) (2,3) (1,2,3)"
s = list(iterable)
return chain.from_iterable(combinations(s, r) for r in range(len(s)+1))
for result in powerset([1, 2, 3]):
print(result)
results = list(powerset([1, 2, 3]))
print(results)
You can also store the object in a variable and use the next()
function to get results from the iterator one by one.