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Converting "day of year" to "year", "month" and "day"

Rui Barradas 
Hello,

Thanks for the data, it makes things easier.

df1 <- read.table("Jibrin_data.txt", header = TRUE)
#'data.frame':	168 obs. of  4 variables:
# $ year: int  1998 1998 1998 1998 1998 1998 1998 1998 1998 1998 ...
# $ day : int  1 2 3 4 5 6 7 8 9 10 ...
# $ Hr  : int  0 0 0 0 0 0 0 0 0 0 ...
# $ SWS : num  344 346 356 332 302 329 395 359 471 392 ...

Here is a simple way of converting the year and day of year columns to a 
column of class "Date".
Like others have said, there are also CRAN packages to handle date/time 
data, my favorite being package lubridate, but base R can do it.


df1$date <- as.Date(paste(df1$year, df1$day),
                     format = "%Y %j",
                     origin = "1998-01-01")

head(df1)
#  year day Hr SWS       date
#1 1998   1  0 344 1998-01-01
#2 1998   2  0 346 1998-01-02
#3 1998   3  0 356 1998-01-03
#4 1998   4  0 332 1998-01-04
#5 1998   5  0 302 1998-01-05
#6 1998   6  0 329 1998-01-06


Hope this helps,

Rui Barradas


?s 06:48 de 16/01/21, Jibrin Alhassan escreveu:

Thread (17 messages)

Jibrin Alhassan Converting "day of year" to "year", "month" and "day" Jan 15 Rui Barradas Converting "day of year" to "year", "month" and "day" Jan 15 Bert Gunter Converting "day of year" to "year", "month" and "day" Jan 15 Bill Dunlap Converting "day of year" to "year", "month" and "day" Jan 15 Martin Møller Skarbiniks Pedersen Converting "day of year" to "year", "month" and "day" Jan 15 Jim Lemon Converting "day of year" to "year", "month" and "day" Jan 15 Jibrin Alhassan Converting "day of year" to "year", "month" and "day" Jan 15 Rui Barradas Converting "day of year" to "year", "month" and "day" Jan 15 Peter Dalgaard Converting "day of year" to "year", "month" and "day" Jan 16 Jibrin Alhassan Converting "day of year" to "year", "month" and "day" Jan 17 Jeff Newmiller Converting "day of year" to "year", "month" and "day" Jan 17 Rui Barradas Converting "day of year" to "year", "month" and "day" Jan 17 Jibrin Alhassan Converting "day of year" to "year", "month" and "day" Jan 17 Jibrin Alhassan Converting "day of year" to "year", "month" and "day" Jan 20 Jibrin Alhassan Converting "day of year" to "year", "month" and "day" Jan 20 Jibrin Alhassan Converting "day of year" to "year", "month" and "day" Jan 20 Jibrin Alhassan Problem on Converting "day of year" to "year", "month" and "day" has been solved Jan 21