for controlling the treatment of NAs.
If TRUE, missing values in the data are put last; if
FALSE, they are put first; if NA, they are removed.
decreasing
logical. Should the sort order be increasing or
decreasing?
Details
ORDER is a new generic function which aims at providing
the functionality of the non-generic base function order
for arbitrary objects. Currently, there is only a default method which
simply calls order. For objects (more precisely if
is.object is TRUE) order
leverages the generic xtfrm. Thus, to assure ordering
works, one can supply either a method to xtfrm or to ORDER
(or both).