New submission from Paul <pyt...@paulkoppen.com>:
The collections docs state: "Several mathematical operations are provided for combining Counter objects to produce multisets (counters that have counts greater than zero)." I am surprised at the clear level of decision into conflating counters with multisets. Why break all functionality for negative counts in favour of multisets? Why not create a Multiset object for multisets? One example use of negative counts is in factorisation (https://bugs.python.org/msg368298 will be surprised counters don't count) 18 = 2**1 * 3**2 --> x18 = Counter({2: 1, 3: 2}) 4 = 2**2 --> x4 = Counter({2: 2}) To compute 18/4 in this representation (which I believe is exactly precisely a count), one would expect 18/4 = 2**-1 * 3**2 --> x4_5 = x18 - x4 = Counter({2: -1, 3: 2}) But instead, x18 - x4 = Counter({3: 2}) = 9 ??? This is just an example. The use case for negative counts is plain and obvious. The question is: why does collections break counter behaviour in favour of conflation with multisets? Why not have two objects: Counter for counters and Multiset for multisets? ---------- components: Library (Lib) messages: 369867 nosy: wpk- priority: normal severity: normal status: open title: Conflation of Counter with Multiset type: behavior versions: Python 3.10, Python 3.5, Python 3.6, Python 3.7, Python 3.8, Python 3.9 _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue40764> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
