Given a year and a day (in Julian day), how can I extract the month? For eg
Year <- '2000'
Doy <- '159'
I want to extract the month for the above Year and Doy. I thought first I will convert this into date and then extract the month out of it using format(mydate,"%m")
# first convert into date and then extract the month
as.Date(paste0(Year'-',Doy), format = '%Y-%d')
NA
This gives me NA.
%d is for day of month. %j is for day of year where Jan 1 is day of year 1, Jan 2 is day of year 2, ..., Dec 31 is day of year 365 (or 366 on leap years). See?strptime for the percent codes.
Year <- '2000'
Doy <- '159'
date <- as.Date(paste(Year, Doy), format = "%Y %j"); date
## [1] "2000-06-07"
as.numeric(format(date, "%m")) # month number
## [1] 6
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