On Mon, 30 Jun 2003, William Briggs wrote: > I have files which have columns of data that look like this: > > DOB > 9/27/1964 > ... > > That is, dates in month/day/year format. When variables like DOB are read > in, they are converted to factors.
Why? You can avoid that, of course. > So, I wrote this to convert from date to age in years: > > age<-function(x) > {as.numeric(Sys.time()-strptime(as.character(x),format="%m/%d/%Y"))/365.25} > > This isn't very precise or pretty, but it works. > > Does anybody have something better? Convert to POSIXlt and compare differences in years, months, days etc. Write an extension to difftime() to handle years and contribute it? -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help