Have you not heard of the phrase, n-dimensional array? Or the phrase, APL/J is an array language? With respect to those phrases, it seems odd to think that arrays are limited in rank to 2.
Anyway, what is an array? Answer: http://www.jsoftware.com/papers/array.htm On Thu, Oct 20, 2011 at 10:28 PM, Alan Stebbens <[email protected]> wrote: > On Oct 20, 2011, at 9:37 PM, Roger Hui wrote: > >>> The object on which verbs operate, that is, a noun, can be either an array, >>> or a scalar. >> >>> So a noun is either a scalar or an array. >> >> But a scalar is an array. See >> http://www.jsoftware.com/jwiki/Essays/Scalars (cited before). >> >> "Noun" is taken in the sense that it is used in lots of documents, >> where it means "array". > > Thanks for the reminder on that link. > > Given those discussions, even though it seems counter-intuitive, I stand > corrected. > > A scalar (aka element) is a zero-rank array. > A vector (aka list) is a one-rank array. > A matrix (aka table aka "array") is a two-rank array. > > The confusion comes from the ambiguous, everyday usage of "array" versus the > more exact APL/J definition, which I'll call "Array". > > Using "noun" to mean Array is less confusing, but if someone then forgets (as > I did) that Array means more than just a 2-rank array, the confusion returns > anyway. > > J is hard enough as it is, but "array" having the everyday meaning alongside > the APL/J meaning (Array) is really quite confusing to explain. > > Perhaps we should all use more caution in how we reference rank-2 objects? > > To avoid confusion entirely, perhaps we should Use "matrix" or "table" to > reference the 2-rank objects (instead of "array"), and use "noun" to mean the > more general, any-rank object? > > BTW, the data warehouse/business intelligence field calls a multi-dimensional > (rank-3 or more) object a "cube". > > > > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
