[R] Problem at subsetting matrix by using dimnames

[Agustin Lobo]

Given:

 > mitest <- matrix(1:16,ncol=4)
 > dimnames(mitest)[[1]] <- c("a","b","c","d")
 > dimnames(mitest)[[2]] <- c("a","b","c","d")
 > mitest
  a b  c  d
a 1 5  9 13
b 2 6 10 14
c 3 7 11 15
d 4 8 12 16

I can do:
 > mitest[cbind(c(1,2,3),c(2,3,2))]
[1]  5 10  7

but using the names does not work:
 > mitest[cbind(c("a","b","c"),c("b","c","b"))]
[1] NA NA NA NA NA NA

despite the fact that
 > mitest["a","b"]
[1] 5

works fine.

How can I do the equivalent of
 > mitest[cbind(c(1,2,3),c(2,3,2))]

using row and column names?

Thanks

Agus


-- 
Dr. Agustin Lobo
Institut de Ciencies de la Terra "Jaume Almera" (CSIC)
LLuis Sole Sabaris s/n
08028 Barcelona
Spain
Tel. 34 934095410
Fax. 34 934110012
email: Agustin.Lobo at ija.csic.es
http://www.ija.csic.es/gt/obster