[Python-ideas] Empty set, Empty dict

[Philipp A.]

of course it’s ugly, but it’s also obvious that it had to be suggested,
because it’s the only obvious idea.

which leaves us with either a non-obvious idea or no empty set literal,
which is a bit sad and inconsistent.

if i’d develop a language from scratch, i’d possibly use the following
empty literals:

[] = list; () = tuple, {} = set
[:] = ordered dict, (:) = named tuple, {:} = dict

but that ship has sailed.


2014-06-10 18:39 GMT+02:00 Guido van Rossum <guido at python.org>:

> No. Jeez. :-(
>
>
> On Tue, Jun 10, 2014 at 9:25 AM, Ryan Gonzalez <rymg19 at gmail.com> wrote:
>
>> +1 for using {,}.
>>
>>
>> On Tue, Jun 10, 2014 at 4:07 AM, Wichert Akkerman <wichert at wiggy.net>
>> wrote:
>>
>>> Victor Stinner wrote:
>>>
>>> 2014-06-10 8:15 GMT+02:00 Neil Girdhar <mistersheik at gmail.com <https://mail.python.org/mailman/listinfo/python-ideas>>:
>>>
>>>
>>>
>>>
>>> >* I've seen this proposed before, and I personally would love this, but my
>>> *>* guess is that it breaks too much code for too little gain.
>>> *>>* On Wednesday, May 21, 2014 12:33:30 PM UTC-4, Frédéric Legembre wrote:
>>> *>>>>>>*    Now   |  Future  |
>>> *>>* ----------------------------------------------------
>>> *>>*    ()    |   ()     |  empty tuple  ( 1, 2, 3 )
>>> *>>*    []    |   []     |  empty list   [ 1, 2, 3 ]
>>> *>>*    set() |   {}     |  empty set    { 1, 2, 3 }
>>> *>>*    {}    |   {:}    |  empty dict   { 1:a, 2:b, 3:c }
>>> *
>>>
>>> Your guess is right. It will break all Python 2 and Python 3 in the world.
>>>
>>> Technically, set((1, 2)) is different than {1, 2}: the first creates a
>>> tuple and loads the global name "set" (which can be replaced at
>>> runtime!), whereas the later uses bytecode and only store values
>>> (numbers 1 and 2).
>>>
>>> It would be nice to have a syntax for empty set, but {} is a no-no.
>>>
>>>
>>> Perhaps {,} would be a possible spelling. For consistency you might want
>>> to allow (,) to create an empty tuple as well; personally I would find that
>>> more intuitive that (()).
>>>
>>> Wichert.
>>>
>>>
>>>
>>>
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>>
>>
>>
>> --
>> Ryan
>> If anybody ever asks me why I prefer C++ to C, my answer will be simple:
>> "It's becauseslejfp23(@#Q*(E*EIdc-SEGFAULT. Wait, I don't think that was
>> nul-terminated."
>>
>>
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>>
>
>
>
> --
> --Guido van Rossum (python.org/~guido)
>
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