I am trying to convert a date into a julian date. I have this data frame
diff yr mo dy hr
1 3.174583 1873 12 1 1
2 2.874583 1873 12 1 3
3 2.574583 1873 12 1 5
4 2.074583 1873 12 1 7
5 1.774583 1873 12 1 9
6 1.474583 1873 12 1 11
and for every row I want to assign the number of days since a particular date (e.g. "1870-01-01").
I tried like this
julian(as.Date(paste(dep$yr,dep$mo,dep$dy,sep="/"),"%Y/%m/%d"))
but this gives me the days since "1970-01-01".. If I try to set the origin
julian(as.Date(paste(dep$yr,dep$mo,dep$dy,sep="/"),"%Y/%m/%d"),origin = paste(1870,1,1,sep="-"))
then I get this error
Error in unclass(x) - unclass(origin) :
non-numeric argument to binary operator
Can some one help me?
Many thanks
Using ISOdate
here and a proper origin date value should help you
julian(with(dep, ISOdate(yr,mo,dy,hr)), origin=as.Date("1870-1-1"))
# Time differences in days
# [1] 1430.042 1430.125 1430.208 1430.292 1430.375 1430.458