Dear Jeff, 2014-05-21 9:33 GMT+02:00 Jeff Newmiller <jdnew...@dcn.davis.ca.us>:
> You did not show us how "x" was created, so we cannot tell whether this > indicates a bug or not. My bet would be that "x' was created in some way > that bypassed the standard POSIXct creation code. > I debugged it, this morning: The problem stems from code like this: > x <- range(..., df$date, ..., na.rm = TRUE) where the data frame "df" is created by an sqlQuery()-call using RODBC (on windows), which returns an empty result set. The data.frame looks like this: > str(df) 'data.frame': 0 obs. of 2 variables: $ id : Factor w/ 12 levels "IT_001",..: $ date : chr (Note: first column is forced to be a factor with specific levels using code not shown.) > dput(df) structure(list(tu = structure(integer(0), .Label = c("IT_001", "IT_012"), class = "factor"), id = character(0), date = character(0)), .Names = c("id","date" ), row.names = integer(0), class = "data.frame") (Note: I edited the output for brevity, hope I didn't break it) This seems to cause other arguments to be coerced to character: > range(1:10, df$date, na.rm=TRUE) [1] "1" "9" > range(c(as.POSIXct("2014-01-01"), as.POSIXct("2013-01-01")), df$date)) [1] "2013-01-01 CET" "2014-01-01 CET" > dput(range(c(as.POSIXct("2014-01-01"), as.POSIXct("2013-01-01")), df$date)) structure(c("1356994800", "1388530800"), class = c("POSIXct", "POSIXt")) I would say, RODBC or the layers it's building on, is to blame. Note that your timezone specification is not atypical for output shorthand > but may not yield consistent results for input on different OS or locale > combinations. I think "Etc/GMT-1" or "Europe/Amsterdam" will be more > reliable depending on your typical data sources. > I read these dates from a database and timezones are added by the driver or db interface layer in R (can't tell which layer is responsible), they are not present in the database. > 1k > I'm 10k on KGS and 14k on DGS. Best regards, Jens [[alternative HTML version deleted]] ______________________________________________ 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.