Hi,
I have R code like so:
num.columns.back.since.last.occurence <- function(m, outcome) {
nrows <- dim(m)[1];
ncols <- dim(m)[2];
res <- matrix(rep.int(0, nrows*ncols), nrow=nrows);
for(row in 1:nrows) {
for(col in 2:ncols) {
res[row,col] <- if(m[row,col-1]==outcome) {0} else
{1+res[row,col-1]}
}
}
res;
}
but on the very large matrices I apply this the execution times are a
problem. I would appreciate any help to rewrite this with more
"standard"/native R functions to speed things up.
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