[R] julian day form POSIXt object

[maxbre]

hello all,

this is my reproducible example data frame

test<-structure(list(date = structure(c(1262300400, 1262304000, 1262304000, 
1262307600, 1262307600, 1262311200, 1262311200, 1262314800, 1262314800, 
1262318400, 1262318400, 1262322000, 1262322000, 1262325600, 1262325600, 
1262329200, 1262329200, 1262332800, 1262332800, 1262336400, 1262336400, 
1262340000, 1262340000, 1262343600, 1262343600, 1262347200, 1262347200, 
1262350800, 1262350800, 1262354400, 1262354400, 1262358000, 1262358000, 
1262361600, 1262361600, 1262365200, 1262365200, 1262368800, 1262368800, 
1262372400, 1262372400, 1262376000, 1262376000, 1262379600, 1262379600, 
1262383200, 1262383200, 1262386800), class = c("POSIXct", "POSIXt"
), tzone = "")), .Names = "date", row.names = c(NA, -48L), class =
"data.frame")

given that, my objective is to create a new variable accounting for the
julian day (i.e. the number of consecutive days elapsed from a fixed origin
date)

and these are (among many others) my (most) unsuccessful attempts…

library(chron)
#not working!
test$jday<-julian(test$date, origin=as.POSIXct(test$date))

#not working!
test$jday<-julian(test$date, origin=test$date)

#not working!
test$jday <-julian(as.Date(test$date, "%m"),
                   as.Date(test$date, "%d"),
                   as.Date(test$date, "%Y"),
                   origin=c(month=1, day=0, year=2010))


any help for this?

thanks a lot

max


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