[issue30196] Add __matmul__ to collections.Counter

[Jáchym Barvínek]

New submission from Jáchym Barvínek:

The class collections.Counter should semantically contain only numbers, so it makes sense to define dot product od Counters, something like this:

def __matmul__(self, other):
  return sum(self[x] * other[x] for x in self.keys() | other.keys())

I find this useful ocassionaly.

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components: Library (Lib)
messages: 292522
nosy: Jáchym Barvínek
priority: normal
severity: normal
status: open
title: Add __matmul__ to collections.Counter
type: enhancement
versions: Python 3.3, Python 3.4, Python 3.5, Python 3.6, Python 3.7

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue30196>
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