functools.cmp_to_key and itertools.combinations_with_replacement missing

[jayvdb]

functools.cmp_to_key and itertools.combinations_with_replacement are mentioned in https://github.com/PythonCharmers/python-future/blob/6b8341c0412ddf8081151692e9034986a6f867bc/docs/changelog.rst#new-features , however they are not mentioned anywhere else and don't appear to have been added to the repo.

[rodrigc]

@edschofield I ran into the same problem, looking for a backport of functools.cmp_to_key, but couldn't find it. Do you have the implementation somewhere, but forgot to add it?

[edschofield]

Thanks for the feedback. You're right ... it looks like they are missing. I haven't been able to find them in my git history either.

I have added cmp_to_key to the v0.16.x branch. Would one of you like to submit a pull request for combinations_with_replacement? I'd be happy to including it in the upcoming v0.16 release.

[jayvdb]

There are two sample implementations at https://docs.python.org/2/library/itertools.html#itertools.combinations_with_replacement

The first one is described as Roughly equivalent to:, which suggests that the first implementation is not 100% correct. :/

There are a bunch of tests in cpython which can be used to check any implementation.

$ grep def.*combinations_with_replacement cpython/Lib/test/test_itertools.py
    def test_combinations_with_replacement(self):
    def test_combinations_with_replacement_overflow(self):
    def test_combinations_with_replacement_tuple_reuse(self):
    def test_combinations_with_replacement(self):
    def test_combinations_with_replacement(self):
    def test_combinations_with_replacement_sizeof(self):

I've created #242 about whether we can borrow PSF licensed code/tests.