I understand the concept, but no real use case comes to my mind, and certainly I personally have not needed this. Itertools is kept extremely minimal by design, containing only a small set of orthogonal primitives. The recipes in its docs contain others, as does more-itertools. This feels like something that belongs, perhaps, in more-itertools. On Wed, Dec 9, 2020 at 4:17 AM <aurelien.lambert.89@gmail.com> wrote:
Hi
I like using itertools for creating long strings while not paying the cost of intermediate strings (by eventually calling str.join on the whole iterator). However, one missing feature is to mimic the behavior of str.join as an iterator: an iterator that returns the items of an iterable, separated by the separator. I suggest name "interleave" or "join" (whichever is the most clear / least ambigous).
def interleave(sep, iterable): """ Makes an iterator that returns elements from an iterable, separated by the separator. """ notfirst = False for i in iterable: if notfirst: yield sep else: notfirst = True yield i
Could imagine a more elaborate implementation that can take several iterators, and would be equivalent to lambda chain_zip_interleave sep, *iterables: itertools.chain.from_iterable(interleave((sep,), zip(*iterables))) But that may be seriously overkill, and I have hard time describing it. _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-leave@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/YWT5BV... Code of Conduct: http://python.org/psf/codeofconduct/
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