puzzled by math on date-time objects
Stavros Macrakis wrote:
It does seem sensible that median and quantile would work for the POSIXct, Date, and other classes for which they are logically well-defined, but strangely enough, they do not (except for odd-length input). The summary function has a special case (summary.POSIXct) which does the straightforward, obvious thing here. I do not understand why this is not done by median and quantile themselves. Conversely, for the complex class, median and quantile do not give an error but instead produce meaningless results
median, but not quantile, seems to fail on complex:
median(0i)
# error, needs numeric
quantile(0i)
# fine
the latter is a presumably a bug, because it doesn't follow the
documentation, ?quantile:
"
quantile(x, ...)
Arguments:
x: numeric vectors whose sample quantiles are wanted. Missing
values are ignored.
"
and complex is not numeric:
is.numeric(0i)
# FALSE
since the complexes do not form an ordered field).
well, in r complexes are not comparable, but they can be sorted:
0i < 1i
# no go
sort(c(0i, 1i))
# fine
vQ