For most types that implement __add__, `x + x` is equal to `2 * x`. That is true for all numbers, list, tuple, str, timedelta, etc. -- but not for collections.Counter. I can add two Counters, but I can't multiply one by a scalar. That seems like an oversight.
It would be worthwhile to implement multiplication because, among other reasons, Counters are a nice representation for discrete probability distributions, for which multiplication is an even more fundamental operation than addition. Here's an implementation: def __mul__(self, scalar): "Multiply each entry by a scalar." result = Counter() for key in self: result[key] = self[key] * scalar return result def __rmul__(self, scalar): "Multiply each entry by a scalar." result = Counter() for key in self: result[key] = scalar * self[key] return result
_______________________________________________ Python-ideas mailing list Pythonfirstname.lastname@example.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/