On Sat, May 9, 2015 at 12:55 AM, peter dalgaard <pda...@gmail.com> wrote: > >> On 09 May 2015, at 02:53 , Henrik Bengtsson <henrik.bengts...@ucsf.edu> >> wrote: >> >> Hi, >> >> I spotted what looks like another(*) mistake in 'R Language >> Definition' on how subsetting should work. In Section 'Indexing >> matrices and arrays' >> [http://cran.r-project.org/doc/manuals/r-release/R-lang.html#Indexing-matrices-and-arrays] >> one can read >> >> "Negative indices are not allowed in indexing matrices." > > Parse error: I believe that this is intended to mean > > "Indexing matrices may not contain negative indices" > > not > > "You cannot use negative indices when indexing matrices". > > This is consistent with the help page: > > " > A third form of indexing is via a numeric matrix with the one > column for each dimension: each row of the index matrix then > selects a single element of the array, and the result is a vector. > Negative indices are not allowed in the index matrix. > " > > Rephrasing would seem to be in order....
Ah... definitely a "parse error" (I read it as a new paragraph). I second rephrasing this; your ""Indexing matrices may not contain negative indices" is non-ambiguous. Thanks Peter /Henrik > > -pd > >> >> but this is not true, e.g. >> >>> x <- matrix(1:12, nrow=4) >>> x >> [,1] [,2] [,3] >> [1,] 1 5 9 >> [2,] 2 6 10 >> [3,] 3 7 11 >> [4,] 4 8 12 >> >>> x[c(-2,-4),] >> [,1] [,2] [,3] >> [1,] 1 5 9 >> [2,] 3 7 11 >> >> /Henrik >> >> (*) https://stat.ethz.ch/pipermail/r-devel/2015-May/071091.html [docs >> have been fixed] >> >> ______________________________________________ >> R-devel@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-devel > > -- > Peter Dalgaard, Professor, > Center for Statistics, Copenhagen Business School > Solbjerg Plads 3, 2000 Frederiksberg, Denmark > Phone: (+45)38153501 > Email: pd....@cbs.dk Priv: pda...@gmail.com > > > > > > > > ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel