Two solutions:
1) Follow the Posting Guide
2) Use the function help.request() [new to R-2.8.0] to figure how
what steps to take.
Each method leads to the solution here:
http://cran.r-project.org/doc/FAQ/R-FAQ.html#Why-do-my-matrices-lose-dimensions_003f
HTH,
Chuck
On Tue, 21 Oct 2008, Pedroso MOACIR wrote:
Hi all,
Why subscripting a one column matrix drops one dimension?
x<- matrix(rnorm(100), ncol=1)
str(x)
num [1:100, 1] -0.413 -0.845 -1.625 -1.393 0.507 ...
str(x[20:30,])
num [1:11] -0.315 -0.693 -0.771 0.448 0.204 ...
str(x[20:30])
num [1:11] -0.315 -0.693 -0.771 0.448 0.204 ...
This breaks:
cov(x)
[,1]
[1,] 0.9600812
cov(x[20:30])
Erreur dans cov(x[20:30]) : fournir 'x' et 'y' ou bien 'x' en matrice
And this behavior is braking function clustIndex (when used with
unidimensional data),
from the package cclust, file Rindexes.R, lines 137-147:
ttww <- function(x, clsize, cluster)
{
n <- sum(clsize)
k <- length(clsize)
w<-0
tt <- cov(x)*n
for (l in 1:k)
w<- w+cov(x[cluster==l,])*clsize[l]
zttw <- list(tt=tt, w=w)
return(zttw)
}
Any way around it?
Thank you.
Moacir Pedroso Jr.
Embrapa - Empresa Brasileira de Pesquisa Agropecuária
(on leave at INRA - Instutute National de la Recherche Agronomique)
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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Charles C. Berry (858) 534-2098
Dept of Family/Preventive Medicine
E mailto:[EMAIL PROTECTED] UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901
______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
