[R] Faster way of binding multiple rows of data than rbind?

From: Ken Termiso <jerk_alert_at_hotmail.com>
Date: Tue 08 Mar 2005 - 03:37:02 EST


Hi all,

I have a vector that contains the row numbers of data taken from several filtering operations performed on a large data frame (20,000rows x 500cols).

In order to output this subset of data, I've been looping through the vector containing the row numbers (keepRows).

output <- data.frame(row.names = rownames(bigMatrix))

for(i in keepRows)
{

        output <- rbind(output, bigMatrix[i, ]) }

As you may guess, doing all of these rbinds takes a LOT of time, so I'm wondering if there's a workaround where I can maybe use an intermediate matrix-like object to store the loop output, and then coerce it back to a data frame after the loop is complete??

Thanks in advance,
Ken



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