r - Convert date without year into Julian day (number of days since start of the year) -

i have date need convert julian days. data have

date <- c("21-jul", "14-jul", "08-jul", "08-jul","16-jul") class(date)  [1] "character" 

i want convert date julian days. above dates, julian days be:

date 202,195,189,189,197  

i found function as.posixlt converts date julian day. e.g.

tmp <- as.posixlt("16jun10", format = "%d%b%y") tmp$yday # [1] 166 

but needs date in particular order including year not have. there way convert dates characters , not have year in julian?

also, year not leap year.

julian days imply day of year 1st jan 1, 2nd jan 2 , on....

base r has function julian can produce looking paste0 , as.date.

julian(as.date(paste0("1970-", date), format="%y-%d-%b")) [1] 201 194 188 188 196 attr(,"origin") [1] "1970-01-01" 

note counted number of days january 1, 1970 (it starts @ 0), can add 1 desired result.

julian(as.date(paste0("1970-", date), format="%y-%d-%b")) + 1 [1] 202 195 189 189 197 

i manually checked 1970 not leap year:

seq(as.date("1970-02-25"), as.date("1970-03-02"), by="day") [1] "1970-02-25" "1970-02-26" "1970-02-27" "1970-02-28" "1970-03-01" "1970-03-02" 

for future reference, possible set starting point yourself, using origin argument as.date:

julian(as.date(paste0("1980-", date), format="%y-%d-%b"), origin=as.date("1980-01-01")) [1] 202 195 189 189 197 attr(,"origin") [1] "1980-01-01" 

as should clear, origin can set date wish, used calculate number of days following (or preceding) date.