Is this a desirable change? I would have expected sort to be equivalent to using order.
Thanks, Stephen -----Original Message----- From: Duncan Murdoch [mailto:[EMAIL PROTECTED] Sent: Thursday, August 03, 2006 11:33 AM To: Ponzio, Stephen [CIB-LAVA] Cc: r-devel@stat.math.ethz.ch; [EMAIL PROTECTED] Subject: Re: [Rd] sort changes datatype of operand (PR#9121) On 8/3/2006 10:34 AM, [EMAIL PROTECTED] wrote: > Full_Name: Stephen Ponzio > Version: 2.3.1 > OS: Windows > Submission from: (NULL) (199.67.138.42) > > > Given a vector of dates, sort returns a vector of numerics instead of dates. > This is different from the behavior in version 2.2, where dates were returned. > In this respect, sort is not equivalent to order. > >> dates <- seq(Sys.Date(), len=5, by="1 day") > >> dates[order(dates)] > [1] "2006-08-03" "2006-08-04" "2006-08-05" "2006-08-06" "2006-08-07" >> sort(dates) > [1] 13363 13364 13365 13366 13367 > >> class(dates[order(dates)]) > [1] "Date" >> class(sort(dates)) > [1] "numeric" This is not a bug, it's documented behaviour in ?sort: > > As from R 2.3.0, all attributes are removed from the return value > except names, which are sorted. (If 'partial' is specified even > the names are removed.) Note that this means that the returned > value has no class, except for factors and ordered factors (which > are treated specially and whose result is transformed back to the > original class). The problem is that some classes assume a particular ordering for values; sort can mess them up. If you know that's not the case, you can protect the class yourself: cl <- class(dates) sorteddates <- sort(dates) class(sorteddates) <- cl You could put this into your own sort.Date function, but it won't be called automatically: sort is not a generic. sort.Date <- function(x) { cl <- class(x) structure(sort(x), class=cl) } Duncan Murdoch ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
