On Sat, Jul 7, 2018 at 11:19 PM, Gabe Becker <becker.g...@gene.com> wrote: > Hadley, > > > On Sat, Jul 7, 2018 at 1:32 PM, Hadley Wickham <h.wick...@gmail.com> wrote: >> >> On Sat, Jul 7, 2018 at 1:50 PM, Gabe Becker <becker.g...@gene.com> wrote: >> > Hadley, >> > >> >> >> >> I was thinking primarily of completing the set of is.matrix() and >> >> is.array(), or generally, how do you say: is `x` a 1d dimensional >> >> thing? >> > >> > >> > Can you clarify what you mean by dimensionality sense and specifically >> > 1d >> > here? >> >> What do we call a vector that is not an array? (or matrix) >> >> What do we call an object that acts 1-dimensional? (i.e. has >> length(dim()) %in% c(0, 1)) ? > > > > Right, or even (length(dim()) == 0 || sum(dim() > 1) <= 1) > > but that is exactly my point, those two(/three) sets of things are not the > same. 1d arrays meet the second definition but not the first. Matrices and > arrays that don't meet either of yours would still meet mine. Which > definition are you proposing strictly define what a vector is?
I am not proposing any definition. I am enquiring if there is a definition in base R. The answer appears to be now. > Another completely unrelated way to define vector, btw, is via the vector > interface (from what I recall this is roughly [, [[, length, and format > methods, though I'm probably forgetting some). This is (more or less) > equivalent to defining a vector as "a thing that can be the column of a > data.frame and have all the base-provided machinery work". I don't know if that definition is adequate because a call would be a vector by that definition. I'm pretty sure a call does not make sense as a data frame column. Also technically data frames don't require their columns to have equal length(), but equal NROW(). So the spirit of that definition would imply that a matrices and arrays are also vectors, which seems like it might be undesirable. Hadley -- http://hadley.nz ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
