[R] do.call("[", ...) question

Robin Hankin rksh at soc.soton.ac.uk
Wed Sep 8 16:08:09 CEST 2004

Hi again everyone

I have an arbitrarily dimensional array "a" and a list "jj" of length
length(dim(a)).    The elements of jj are vectors of indexes.

How do I use do.call() to extract a[ jj[[1]], jj[[2]], jj[[3]], ...] ?

Toy example follows:

a <- matrix(1:30,5,6)
jj <- list(5:1,6:1)

I want the following

  a[ jj[[1]],jj[[2]] ]

How do I do this?



Of course, the one that works is


but I don't know how long jj is apriori so this won't do.
Robin Hankin
Uncertainty Analyst
Southampton Oceanography Centre
SO14 3ZH
tel +44(0)23-8059-7743
initialDOTsurname at soc.soton.ac.uk (edit in obvious way; spam precaution)

More information about the R-help mailing list