[Rd] Proposal unary - operator for factors
wdunlap at tibco.com
Thu Feb 4 00:49:29 CET 2010
> -----Original Message-----
> From: h.wickham at gmail.com [mailto:h.wickham at gmail.com] On
> Behalf Of Hadley Wickham
> Sent: Wednesday, February 03, 2010 3:38 PM
> To: William Dunlap
> Cc: r-devel at 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 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
For nonnumeric types like POSIXct and factors only
the latter works.
Under my proposal your
order(a, -b, c, d)
order(a, b, c, d, decreasing=c(FALSE,TRUE,FALSE,TRUE))
and it would work for any ordably class without modifications
to any classes.
More information about the R-devel