On Apr 22, 2011, at 12:31 PM, Terry Therneau wrote: > I can't seem to get a histogram of dates: > > tmt910% R --vanilla > > R version 2.13.0 (2011-04-13) > Copyright (C) 2011 The R Foundation for Statistical Computing > ISBN 3-900051-07-0 > ... >> temp <- as.Date(1:200, origin="1970/01/01") >> range(temp) > [1] "1970-01-02" "1970-07-20" >> hist(temp) > Error in .Internal(inherits(x, what, which)) : 'x' is missing > >> traceback() > 3: inherits(breaks, "Date") > 2: hist.Date(temp) > 1: hist(temp) > > Existence of hist.Date implies that this is intended to work. > The MASS version fails in a different way. > >> library(MASS) >> truehist(temp) > Error in Ops.difftime(n, 2) : '%/%' not defined for "difftime" objects
Hi Terry, Try this: temp <- as.Date(1:200, origin="1970/01/01") hist(temp, breaks = "months") There is no default for the 'breaks' argument in hist.Date() and there does not appear to be a check for a missing value for this argument. truehist() does not have a method for Date class objects, but you could do: truehist(as.numeric(temp)) or perhaps use cut.Date() on the vector and create the intervals/breakpoints that you wish to use. HTH, Marc Schwartz ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.