[R] colMeans()

Matteo Mattiuzzi
2009-09-28T12:47:27Z

Hello,

I use the function rowMeans(x,na.rm=T). The result is the mean of valid
values in each row, with NA removed. A for me very important information
is, from how many valid "n" this mean has computed.

The thing is, that I apply this function on many millions of rows, so
the time it takes is multiplied by this factor! (so getting this with
"rowSums(is.na(x))" it takes much to long)

I was trying to look inside the function maybe to get not only the
means but the valid "n" too, but I wasn't able.

Thanks for help Matteo


DI Matteo Mattiuzzi,
Institut für Vermessung, Fernerkundung und Landinformation
Peter Jordan Str. 82
A-1190 Wien

Tel.: 0043/(0)1/47654-5114

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