[Python-ideas] namedtuple literals [Was: RE a new namedtuple]

[Alex Walters]

> -----Original Message-----
> From: Python-ideas [mailto:python-ideas-bounces+tritium-
> list=sdamon.com at python.org] On Behalf Of Michel Desmoulin
> Sent: Sunday, July 30, 2017 4:19 AM
> To: python-ideas at python.org
> Subject: Re: [Python-ideas] namedtuple literals [Was: RE a new namedtuple]
> 
> 
> 
> Le 29/07/2017 à 18:14, Alex Walters a écrit :
> > My $0.02 on the entire series of nametuple threads is… there **might**
> > be value in an immutable namespace type, and a mutable namespace type,
> > but namedtuple’s promise is that they can be used anywhere a tuple can
> > be used.  If passing in kwargs to create the potential replacement to
> > namedtuple is sensitive to dict iteration order, it really isn’t a
> > viable replacement for namedtuple.
> 
> In Python 3.6, kwargs order is preserved and guaranteed. It's currently
> implemented by relying on the non guaranteed dict order. But the 2 are
> not linked. The spec does guaranty that for now on, kwargs order is
> always preserved whether the dict order is or not.

MyNT = namedtuple_replacement('MyNT', 'foo bar')
data = {}
data['bar'] = 8675309
data['foo'] = 525600

MyNT(*data) == (525600, 8675309)   # better be true, or else, we are depending on iteration order.


> 
> >
> >
> >
> > I do feel like there isn’t that big of a usecase for an immutable
> > namespace type as there is for a namedtuple.  I would rather namedtuple
> > class creation be quicker.
> >
> >
> >
> >
> >
> > *From:* Python-ideas
> > [mailto:python-ideas-bounces+tritium-list=sdamon.com at python.org] *On
> > Behalf Of *Chris Barker
> > *Sent:* Friday, July 28, 2017 8:27 PM
> > *To:* Ethan Furman <ethan at stoneleaf.us>
> > *Cc:* Python-Ideas <python-ideas at python.org>
> > *Subject:* Re: [Python-ideas] namedtuple literals [Was: RE a new
> namedtuple]
> >
> >
> >
> > On Thu, Jul 27, 2017 at 7:42 PM, Ethan Furman <ethan at stoneleaf.us
> > <mailto:ethan at stoneleaf.us>> wrote:
> >
> >     How I get the point[0] == 3?  The first definition of an ntuple had
> >     the order as x, y, and since the proposal is only comparing field
> >     names (not order), this (y, x) ntuple ends up being reversed to how
> >     it was specified.
> >
> >
> >
> > I'm not sure there ever was a "proposal" per se, but:
> >
> > ntuple(x=a, y=b)
> >
> >
> >
> > had better be a different type than:
> >
> > ntuple(y=b, x=a)
> >
> > but first we need to decide if we want an easy way to make an
> > namedtuple-like object or a SimpleNemaspace-like object....
> >
> >
> >
> > but if you are going to allow indexing by integer, then order needs to
> > be part of the definition.
> >
> >
> >
> > -CHB
> >
> >
> > --
> >
> >
> > Christopher Barker, Ph.D.
> > Oceanographer
> >
> > Emergency Response Division
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> >
> > Chris.Barker at noaa.gov <mailto:Chris.Barker at noaa.gov>
> >
> >
> >
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