In addition to Petr's remarks: - why are you doing sum(mtcars)[1]? Do you want the sum of first column of mtcars? In that case you should do sum(mtcars[,1]).
- similar remarks apply to your use of mean and sd. Have you read an introduction to R? Berend > On 14 Nov 2016, at 04:01, moku...@sina.com wrote: > > Hi, > I am working on functions such as sum(), mean() ... >> sum(mtcars)[1] 13942.2> mean(mtcars)[1] NAWarning message:In >> mean.default(mtcars) : NA> sd(mtcars)Error in is.data.frame(x) : ()'double' > why got different reply?Is this a BUG for the current version of R?my version > info:version.string R version 3.3.1 (2016-06-21) > > Thank you very much for the help. > mokuram > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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 -- To UNSUBSCRIBE and more, see 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.