> -----Original Message----- > From: h.wick...@gmail.com [mailto:h.wick...@gmail.com] On > Behalf Of Hadley Wickham > Sent: Wednesday, February 03, 2010 3:38 PM > To: William Dunlap > Cc: r-devel@r-project.org > Subject: Re: [Rd] Proposal unary - operator for factors > > > It wouldn't make sense in the context of > > vector[-factor] > > True, but that doesn't work currently so you wouldn't lose anything. > However, it would make a certain class of problem that used to throw > errors become silent. > > > Wouldn't it be better to allow order's decreasing argument > > to be a vector with one element per ... argument? That > > would work for numbers, factors, dates, and anything > > else. Currently order silently ignores decreasing[2] and > > beyond. > > The problem is you might want to do something like order(a, -b, c, -d)
Currently, for numeric a you can do either order(-a) or order(a, decreasing=FALSE) For nonnumeric types like POSIXct and factors only the latter works. Under my proposal your order(a, -b, c, d) would be order(a, b, c, d, decreasing=c(FALSE,TRUE,FALSE,TRUE)) and it would work for any ordably class without modifications to any classes. Bill > Hadley > > -- > http://had.co.nz/ > ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
