[Python-ideas] Unpacking a dict

[Franklin? Lee]

Then is it too late to point out that the desired goal (of dumping
part of a dict into the local namespace) is really similar to
importing?

Something I am most definitely not suggesting:
        from some_dict dict_import a, b, c

Related, a version that works for Enums:
        from some_Enum attr_import *
        from vars(some_enum) dict_import *

Again, I'm not suggesting these syntaxes (and I hope everyone else
hates them), just pointing out that it's more similar to imports than
destructuring.

On Wed, May 25, 2016 at 11:46 PM, Ethan Furman <ethan at stoneleaf.us> wrote:
> On 05/25/2016 07:56 PM, Chris Angelico wrote:
>>
>> On Thu, May 26, 2016 at 12:43 PM, Ethan Furman wrote:
>
>
>>> I'll meet you halfway:
>>>
>>>    {a, b} = some_dict
>>>
>>> which is currently a SyntaxError, so little backwards compatibility
>>> concerns, plus it clearly state the mapping should have two elements,
>>> similarly to
>>>
>>>   [a] = some_iterable
>>>
>>> and
>>>
>>>   (b) = some_iterable
>>>
>>> both clearly state that a one-element iterable is being unpacked.
>>>
>>
>> Careful - the second one doesn't:
>>
>> --> (b) = [1, 2, 3]
>> -->
>
>
> Ack.  Right you are, which is why I always use the list form, even on
> tuples.
>
>> I hope there doesn't end up being a confusion between mapping
>> unpacking and set display. Sets are a bit of an odd duck; are they
>> like lists only unordered, or like mappings only without values? I've
>> seen them used both ways, and the syntax is somewhere between the two.
>> Having a syntax that constructs a set if used on the RHS but unpacks a
>> dict if used on the LHS seems to violate syntactic purity, but I'd be
>> happy to let practicality trump that.
>
>
> Given the other issues, I'm happy to let this one die.  Good discussion.
>
> --
> ~Ethan~
>
>
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