Because rank and order are (supposed to be) inverses of each other. For example: > a <- c(3, 1, NA) > a[order(a[rank(a)])] [1] 3 1 NA > a[rank(a[order(a)])] [1] 3 1 NA
BUT > a[order(a[rank(a, na.last = FALSE)])] [1] 1 NA 3 > a[rank(a[order(a)], na.last = FALSE)] [1] 1 NA 3 -----Original Message----- From: Alejandro Munoz del Rio [mailto:[EMAIL PROTECTED] Sent: Thursday, May 19, 2005 1:01 PM To: [email protected] Subject: [R] reason for na.last=TRUE in rank Dear UseRs, Could someone explain to me why the default behaviour of rank() is to assign the largest rank to missing data > rank(c(3, 1, NA)) [1] 2 1 3 as opposed to what I would hazard would be the expected 2, 1, NA? Despite consistency being the hobgoblin of little minds, of two closely related functions one handles NAs in the same way (order()) but another one doesn't (sort()). order() also uses the "NA last" rule by default, whereas sort() removes NAs. alejandro ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
