[R] aperm() and as.list() args to "["

[Robin Hankin]

Hi everyone.

I'm playing with aperm():

a <- 1:24
dim(a) <- c(2,3,2,2)
permutation <-  c(1,2,4,3)
b <- aperm(a,permutation)


So if my understanding is right,

a[1,3,2,1] ==  b[c(1,3,2,1)[permutation] ]

but this isn't what I want because the RHS evaluates to a vector, and
I am trying to identify a single element of b.

How do I modify the RHS to give what I want?


Following aren't right  either:
b[as.vector(c(1,3,2,1)[permutation]) ]
b[as.list(c(1,3,2,1)[permutation]) ]


OBattempt:
eval(parse(text=paste("b[",paste(c(1,3,2,1)[permutation],collapse=","),"]")))

which DOES work, but is ghastly!

-- 
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)