Generating a day of year column from date column in R? [duplicate]-CodePudding

I am attempting to take a column of the format POSIXct (or, if necessary, chr) and generate a new column that represents the day of year for that date (some number from 1-366, depending on the year). For example, say I have a row with value "2020-11-16" in the format POSIXct, how can I extract the day of year (day 321 in this case) and do so over the course of an entire column?

CodePudding user response：

Hi you can use the lubridate- Package

> library(lubridate)
> yday(as.POSIXct("2020-11-16"))
[1] 321

of course this also works with a vector/ column:

v<-paste0("2020-11-",1:30)
yday(as.POSIXct(v))