Hi, I have written the following function to check whether a vector has elements satisfying monotonicity.
is.monotone <- function(vec, increase=T){ # check for monotonicity in time-stamp data for cortisol collection ans <- TRUE vec.nomis <- vec[!is.na(vec)] if (increase & any(diff(vec.nomis,1) < 0, na.rm=T)) ans <- FALSE if (!increase & any(diff(vec.nomis,1) > 0, na.rm=T)) ans <- FALSE ans } This works correctly, but I get this error message as below. > x <- 2:10 > is.monotone(x) [1] TRUE Warning messages: 1: the condition has length > 1 and only the first element will be used in: if (increase & any(diff(vec.nomis, 1) < 0, na.rm = T)) ans <- FALSE 2: the condition has length > 1 and only the first element will be used in: if (!increase & any(diff(vec.nomis, 1) > 0, na.rm = T)) ans <- FALSE > I am unable to see why the condition should have a length greater than 1, since "any" should give me a single logical value. Can any one tell me what is going on here? ( I am using version 2.1.1 on Windows). Thanks very much, Ravi. -------------------------------------------------------------------------- Ravi Varadhan, Ph.D. Assistant Professor, The Center on Aging and Health Division of Geriatric Medicine and Gerontology Johns Hopkins University Ph: (410) 502-2619 Fax: (410) 614-9625 Email: [EMAIL PROTECTED] ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html