[Python-Dev] Proposal: dict.with_values(iterable)

[Inada Naoki]

On Tue, Apr 23, 2019 at 2:18 AM Chris Barker via Python-Dev
<python-dev at python.org> wrote:
>
> On Fri, Apr 12, 2019 at 10:20 AM Brett Cannon <brett at python.org> wrote:
>>>
>>>
>> This doesn't strike me as needing an optimization through a dedicated method.
>
> maybe a new dict mapping type -- "shared_dict" -- it would be used in places like the csv reader where it makes sense, but wouldn't impact the regular dict at all.
>
> you could get really clever an have it auto-convert to a regular dict when any changes were made that are incompatible with the shared keys...


My current idea is adding builder in somewhere in stdlib (maybe collections?):

  builder = DictBuilder(keys_tuple)
  value = builder(values)  # repeatedly called.

I don't want to add new mapping type because we already have shared key dict,
and changing mapping type may cause backward compatibility problem.


Regards,
-- 
Inada Naoki  <songofacandy at gmail.com>