Dear all, I would like to know the month on a string formatted as "2004-01", using as.Date (not just stripping the string !)
?as.Date says that in case of an incomplete input string, the answer is system-specific. The following has been tested on R 2.4.1, on Ubuntu Linux and WinXP. > mydate <- "2004-01" > as.Date(mydate) Error in fromchar(x) : character string is not in a standard unambiguous format. (I understand that). > as.Date(mydate,format="%Y-%m") NA (is there still ambiguity in my format ??) Investigating a bit, I found a strange behaviour in : > as.Date("2004-01-12",format="%Y-%m-%d") "2005-01-12" > as.Date("2004-01",format="%Y-%m") NA (why can't R see anything ?) > as.Date("2004",format="%Y") "2005-02-09" (month and day are replaced by today's values, normal behaviour). Why can't R see the month, but see the year ? For the moment, I do this ugly thing : > mydate <- paste(mydate,"-01",sep="") in order send an unambiguous string to as.Date. Any idea how I can do better ? Thanks and regards, Nicolas Prune ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.