lib/collections: Allow Counter()*integer.

[abhijeetbodas2001]

This isn't part of the standard multiset operations, but makes sense to be added nonetheless, I feel!

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[abhijeetbodas2001]

IMO, the change is too small to warrant a GH issue (or a NEWS entry), but I am happy to open one if required.

[picnixz]

Please read the devguide first: https://devguide.python.org/getting-started/pull-request-lifecycle/. This requires an issue and a prior discussion (what are the use cases?) Until this feature is accepted, this PR should be closed.

[rhettinger]

Thank you for the suggestion, but I will decline. A counter-to-integer * operation does not match the counter-to-counter + and - operations. Having unexpectedly different semantics would create unnecessary confusion. Likely, that is why "this isn't part of the standard multiset operations".

FWIW, here is an easy way to do what you want:

>>> c = Counter(a=1, b=2, c=3)
>>> Counter({k : v*2 for k, v in c.items()})
Counter({'c': 6, 'b': 4, 'a': 2})

[abhijeetbodas2001]

what are the use cases?

I was (unpleasantly) surprised to find that Counter did not support multiplication with integer while solving a particular puzzle.

So the use-case isn't a "real" one, but I made this PR since this felt natural to have.

But thanks for the reviews nonetheless!