[Python-ideas] Accepting multiple mappings as positional arguments to create dicts

[Daniel Moisset]

In which way would this be different to {**mapping1, **mapping2,
**mapping3} ?

On 8 April 2018 at 22:18, Andrés Delfino <adelfino at gmail.com> wrote:

> Hi!
>
> I thought that maybe dict could accept several mappings as positional
> arguments, like this:
>
> class Dict4(dict):
>>     def __init__(self, *args, **kwargs):
>>         if len(args) > 1:
>>             if not all([isinstance(arg, dict) for arg in args]):
>>                 raise TypeError('Dict4 expected instances of dict since
>> multiple positional arguments were passed')
>>
>>             temp = args[0].copy()
>>
>>             for arg in args[1:]:
>>                 temp.update(arg)
>>
>>             super().__init__(temp, **kwargs)
>>         else:
>>             super().__init__(*args, **kwargs)
>>
>
> AFAIK, this wouldn't create compatibility problems, since you can't pass
> two positional arguments now anyways.
>
> It would be useful to solve the "sum/union dicts" discussion, for example:
> requests.get(url, params=dict(params, {'foo': bar})
>
> Whar are your thoughts?
>
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>


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