CODEWITHSUNDEEP
pythonpython-itertools
Ahmed Tounsi
Ahmed Tounsi

Reputation: 1550

Starting to iterate from a position in an itertools.product object

I'm using the python itertools module to create a generator that iterates from aaa to ccc.

I cant figure out a way to start the iteration from a certain position for example if the input is aba the iteration will continue from that position this is how my code looks like now:

from itertools import product

strings = itertools.product(*["abc"]*3)
for item in strings:
    print("".join(item))

Upvotes: 0

Views: 382

Answers (1)

Patrick Haugh
Patrick Haugh

Reputation: 61014

This method doesn't skip any of the computation, it just drops values until it sees the one it's looking for. This should work on any iterable, but there may be a product specific solution that would allow you to skip generating the values you don't care about.

from itertools import dropwhile, product

def resume(iterable, sentinel):
    yield from dropwhile(lambda x: x != sentinel, iterable)

for t in resume(product('abc', repeat=3), ('a', 'b', 'a')):
    print(*t)

Upvotes: 3

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