Your report is `obviously misleading', as you seem unaware of the standard mathematical definitions. You also seem unaware that R statements are terminated by a newline, so you have a while series of empty statements and should not have the semicolons.
The sum of an empty vector is 0, by definition. The mean of an empty vector is 0/0 = NaN, by definition. The variance and hence the standard deviation are undefined unless n >= 1. None of them are missing, so it would be incorrect to return NA. On Tue, 1 Apr 2003 [EMAIL PROTECTED] wrote: > Full_Name: Klaus Hermann > Version: 1.5.0 > OS: SUNRAY - Unix > Submission from: (NULL) (213.61.59.254) > > > if we produce a numeric vector of length 0 and want compute the sum over its > elements > the sum function returns 0 - this is obviously misleading. Better would be to > return > NA and give a corresponding warning. > There should be a unified strategy to handle vectors of length 0. There is: to use the standard mathematical definitions. One could debate what var(numeric(0)) should be, but we decided that was most consistently an error. > For example the functions sum, mean, sd handle such vectors in a different way > > example: > > classfreq <- c(3,3,3,3); > classfreq <- classfreq[classfreq != 3]; > > sum(classfreq); > mean(classfreq); > sd(classfreq); -- 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-devel
