On Tue, Sep 1, 2020 at 4:57 PM Greg Ewing <greg.ew...@canterbury.ac.nz> wrote:
> On 2/09/20 2:24 am, Steven D'Aprano wrote: > > On Sun, Aug 30, 2020 at 05:49:50PM +1200, Greg Ewing wrote: > >> On 30/08/20 3:06 pm, Steven D'Aprano wrote: > >>> On Thu, Aug 27, 2020 at 11:13:38PM +1200, Greg Ewing wrote: > >>> > >>>> a[17, 42] > >>>> a[time = 17, money = 42] > >>>> a[money = 42, time = 17] > > > > Compares to the majority of realistic examples given in this discussion > > and the PEP, your example doesn't look to me like an item or key lookup. > > It looks more like a function call of some sort. > > > > I know that, in a sense, subscript lookups are like function calls, and > > I also acknowledge that I don't know your intended semantics of that > > example. > > It was a reference to earlier discussions of pandas and xarray, where > there is a notion of axes having names, and a desire to be able to > specify index values by name, for the same reasons that we sometimes > want to specify function arguments by name. > > It's true that you can't tell just by looking at an indexing expression > what the semantics of the keywords are, but the same is true of function > calls. We rely on contextual knowledge about what the function does in > order to interpret the keywords. > > Likewise here. If you know from context that a is an array-like object > with axes named 'time' and 'money', then I think the meaning of the > indexing expression will be quite clear. I also think that it's > something people will naturally expect to be able to use index keywords > for -- to the point that if they can't, their reaction will be > "Why the flipping heck not?" > > Which is why I was somewhat perplexed when it was suggested that we > should discount this use case purely because it wasn't cited in the > original proposal (which turned out to be wrong anyway). > I agree it's a fine use case. Using the currently prevailing proposal (which I steadfastly will refer to as "Steven's proposal") it's quite possible to implement this. -- --Guido van Rossum (python.org/~guido) *Pronouns: he/him **(why is my pronoun here?)* <http://feministing.com/2015/02/03/how-using-they-as-a-singular-pronoun-can-change-the-world/>
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