Hello,
> I could find the maximal set of columns such that there exists a subset of
> rows with non NA values for every column in the set - what is an
> efficient
> way to do that?
Try 'na.exclude' on the transpose matrix.
Example:
set.seed(1)
x <- matrix(1:200, ncol=25)
f <- function(x){x[sample(length(x), 1)] <- NA; x}
x <- t(apply(x, 1, f))
x
x.without.NA <- t(na.exclude(t(x)))
Hope this helps,
Rui Barradas
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