[Python-Dev] syntactic support for sets

Ronald Oussoren ronaldoussoren at mac.com
Mon Feb 6 15:36:06 CET 2006

On Monday, February 06, 2006, at 03:12PM, Donovan Baarda <abo at minkirri.apana.org.au> wrote:

>On Fri, 2006-02-03 at 20:02 +0100, "Martin v. Löwis" wrote:
>> Donovan Baarda wrote:
>> > Before set() the standard way to do them was to use dicts with None
>> > Values... to me the "{1,2,3}" syntax would have been a logical extension
>> > of the "a set is a dict with no values, only keys" mindset. I don't know
>> > why it wasn't done this way in the first place, though I missed the
>> > arguments where it was rejected.
>> There might be many reasons; one obvious reason is that you can't spell
>> the empty set that way.
>Hmm... how about "{,}", which is the same trick tuples use for the empty

Isn't () the empty tuple? I guess you're confusing this with a single element tuple: (1,) instead of (1) (well actually it is "1,")

BTW. I don't like your proposal for spelling the empty set as {,} because that is entirely non-obvious. If {1,2,3} where a valid way to spell a set literal, I'd expect {} for the empty set.


>Donovan Baarda <abo at minkirri.apana.org.au>
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