I was doing some drawing in R and I needed to trim some values to keep the data (x axis) in reasonable limits, but I did not want to loose that info. Therefore, I summed the values that would be trimmed. Since I was repeating this, I wrote a function and commited it to the gdata SVN package repository. It will probably take some time before new version of gdata hits the CRAN, so there is package for MS Windows and a source package. Here it goes in action:

> x <- 1:10
> trimSum(x, n=5)
[1]  1  2  3  4 45
> trimSum(x, n=5, right=FALSE)
[1] 21  7  8  9 10

> x[9] <- NA
> trimSum(x, n=5)
[1]  1  2  3  4 NA
> trimSum(x, n=5, na.rm=TRUE)
[1]  1  2  3  4 36

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