On 10-12-27 5:26 PM, Eduardo de Oliveira Horta wrote:
Hello there
I wish to get the "coordinates" of the minimum element of an array.
For example, if the array were
H = array(c(8:5,1:4),dim=c(2,2,2))
H
, , 1
[,1] [,2]
[1,] 8 6
[2,] 7 5
, , 2
[,1] [,2]
[1,] 1 3
[2,] 2 4
then
min(H)
[1] 1
and
max(H)
[1] 8
Say "idx" were the function I'm looking for. Then, what I'm expecting is
idx(min(H))
[1] 1 1 2
idx(max(H))
[1] 1 1 1
I don't know if anyone has written a function with the exact output you
want, but you can get the vector index using which.min() and
which.max(). Converting that to a vector index is simply a matter of
some modular arithmetic. Here's a quick ugly version:
vector.which.min <- function(H) {
d <- dim(H)
i <- which.min(H) - 1
result <- c()
for (j in seq_along(d)) {
result <- c(result, i %% d[j])
i <- i %/% d[j]
}
result + 1
}
Duncan Murdoch
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