On Sat, Oct 12, 2013 at 8:07 AM, Nick Coghlan <ncoghlan@gmail.com> wrote:

One interesting point is that combining collections.Counter.elements() with itertools.permutations() currently does the wrong thing, since itertools.permutations() *always* considers iterable order significant, while for collections.Counter.elements() it's explicitly arbitrary.

I hadn't thought about it, but as I read the docs for 3.4 (and it's the same back through 2.7), not only would both of these be permissible in a Python implementation:

>>> list(collections.Counter({'a':2,'b':1}).elements())

['a', 'a', 'b']

Or:

>>> list(collections.Counter({'a':2,'b':1}).elements())

['b', 'a', 'a']

But even this would be per documentation (although really unlikely as an implementation):

>>> list(collections.Counter({'a':2,'b':1}).elements())

['a', 'b', 'a']

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