> On Jun 8, 2018, at 1:49 PM, Hadley Wickham <h.wick...@gmail.com> wrote:
>
> Hmmm, yes, there must be some special case in the C code to avoid
> recycling a length-1 logical vector:
Here is a version that (I think) handles Herve's issue of arrays having one or
more 0 dimensions.
subset_ROW <-
function(x,i)
{
dims <- dim(x)
index_list <- which(dims[-1] != 0L) + 3
mc <- quote(x[i])
nd <- max(1L, length(dims))
mc[ index_list ] <- list(TRUE)
mc[[ nd + 3L ]] <- FALSE
names( mc )[ nd+3L ] <- "drop"
eval(mc)
}
Curiously enough the timing is *much* better for this implementation than for
the first version I sent.
Constructing a version of `mc' that looks like `x[i,,,,drop=FALSE]' can be done
with `alist(a=)' in place of `list(TRUE)' in the earlier version but seems to
slow things down noticeably. It requires almost twice (!!) as much time as the
version above.
Best,
Chuck
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