On Thu, Aug 20, 2020 at 09:03:40AM -0400, Random832 wrote: > On Mon, Aug 17, 2020, at 14:00, Christopher Barker wrote: > > From an implementation perspective, the [] operator is another way to > > call __getitem__ and __setitem__. And from that perspective, why not > > have it act like a function call: no arguments, positional arguments, > > keyword arguments, the whole shebang. > > > > But from a language design perspective, the [] operator is a way to > > "index" a container -- get part of the container's contents. And from > > this perspective, no index makes no sense. > > I think it makes perfect sense. Remember that numpy *currently* has a > concept of "no index" [an empty tuple is used for this], it results in > a view of the whole array, or the content as a scalar for a > 0-dimensional array.
I wouldn't necessarily be taking numpy as the gold standard of good API design. Treating a missing index as the object itself makes a certain logical sense. Here's a variable with a subscript: xₑ and here it is again with a missing subscript: x So by analogy, we might say that `x[]` should be treated as just `x`. But honestly that's more likely to be an error, not a feature. I think that zero dimensional arrays are a pretty dubious concept, but if you did have one, since it has *no dimensions* it cannot contain any content at all. > [I've occasionally been tempted to try the same thing on ctypes > objects, incidentally, I think it might be useful to make obj[] > equivalent to obj.value] And what about all the objects that don't have a .value attribute? What's so special about that attribute that subscripting with a missing subscript should return that attribute rather than some other? -- Steve _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/WVE3CS7LFSKWSM7F2DKFLWTS4UST6DOA/ Code of Conduct: http://python.org/psf/codeofconduct/