If you want the vector to be a Date you need to specify a date at least down to the day. Otherwise the date is not well defined and becomes <NA> as you noted.
Perhaps the easiest thing is to give it a particular day of the month, e.g. the first, or the 15 (the "ides"), or ... > x <- as.Date(paste("1990-January", 1, sep="-"), format = "%Y-%B-%d") > x [1] 1990-01-01 Now if you want to display the date suppressing the dummy day, you can > y <- format(x, "%Y-%B") > y [1] "1990-January" Bill Venables http://www.cmis.csiro.au/bill.venables/ -----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Bob Roberts Sent: Tuesday, 31 March 2009 5:14 PM To: r-help@r-project.org Subject: [R] Convert Character to Date Hello, I have a date in the format Year-Month Name (e.g. 1990-January) and R classes it as a character. I want to convert this character into a date format, but when I try as.Date(1990-January, "%Y-%B"), I get back NA. The function strptime also gives me NA back. Thanks. [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org 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. ______________________________________________ R-help@r-project.org 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.