[Rd] R Language Definition: Subsetting matrices with negative indices is *not* an error
Henrik Bengtsson
henrik.bengtsson at ucsf.edu
Sat May 9 02:53:15 CEST 2015
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."
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]
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