histogram of dates
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