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Speed up or alternative to 'For' loop

MacQueen, Don 
How about

for (ir in unique(df$TreeID)) {
  in.ir <- df$TreeID == ir
  df$HeightGrowth[in.ir] <- cumsum(df$Height[in.ir])
}

Seemed fast enough to me.

In R, it is generally good to look for ways to operate on entire vectors
or arrays, rather than element by element within them. The cumsum()
function does that in this example.

-Don

Thread (7 messages)

Trevor Walker Speed up or alternative to 'For' loop Jun 10 Rui Barradas Speed up or alternative to 'For' loop Jun 10 MacQueen, Don Speed up or alternative to 'For' loop Jun 10 David Winsemius Speed up or alternative to 'For' loop Jun 10 MacQueen, Don Speed up or alternative to 'For' loop Jun 10 MacQueen, Don Speed up or alternative to 'For' loop Jun 10 arun Speed up or alternative to 'For' loop Jun 10