[Python-ideas] collections.Counter multiplication

[James K]

Oops I forgot Counter doesn't support operations with scalars, I'm still
proposing the second example


On Thu, May 30, 2013 at 6:21 AM, David Mertz <mertz at gnosis.cx> wrote:

> That "intuitive" behavior certainly wouldn't have been my first--or second
> guess--on seeing the syntax.
>
>
> On Wed, May 29, 2013 at 1:17 PM, James K <jamylak at gmail.com> wrote:
>
>> It should work like this
>>
>>     >>> from collections import Counter
>>     >>> Counter({'a': 1, 'b': 2}) * 2 # scalar
>>     Counter({'b': 4, 'a': 2})
>>     >>> Counter({'a': 1, 'b': 2}) * Counter({'c': 1, 'b': 2}) #
>> multiplies matching keys
>>     Counter({'b': 4})
>>
>>
>> This is intuitive behavior and therefore should be added. I am unsure
>> about division as dividing by a non-existing key would be a division by 0,
>> although division by a scalar is straightforward.
>>
>>
>> On Thu, May 30, 2013 at 12:29 AM, Ned Batchelder <ned at nedbatchelder.com>wrote:
>>
>>>  On 5/29/2013 1:27 AM, James K wrote:
>>>
>>> Can we add a multiplication feature to collections.Counter, I don't see
>>> why not.
>>>
>>>
>>> James, welcome to the list.  To get an idea accepted, you have to do a
>>> few things:
>>>
>>> 1) Explain the idea fully.  I don't understand what "a multiplication
>>> feature" would do.
>>> 2) Explain why the idea is useful to enough people that it should be
>>> added to the standard library.
>>>
>>> These two criteria are not easy to meet.  Sometimes an idea seems
>>> popular, but it turns out that different people want it to behave
>>> differently, or differently at different times (see the discussion about an
>>> itertools.chunked feature).  Sometimes an idea is straightforward enough to
>>> describe, but is useful to too few people to justify adding it to the
>>> standard library.
>>>
>>> Discussing these things doesn't often result in a change to Python, but
>>> does often lead to useful discussion.
>>>
>>> --Ned.
>>>
>>>
>>>
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>>>
>>>
>>>
>>
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>
>
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