Don't know about efficiency but here is one way: # test data A <- matrix(1:54, ncol=6) A[3,3] <- A[6,6] <- A[5,6] <- NA
f <- function(x) ifelse(is.na(x), mean(x, na.rm = TRUE), x) apply(A, 2, f) On 1/30/06, Julie Bernauer <[EMAIL PROTECTED]> wrote: > Hello > > I am sorry fuch such a stupid question. Suppose I have a table of data having > a > lot of NAs and I want to replace those NAs by the mean of the column before NA > replacement. How is it possible to do that efficiently ? > > Thanks in advance, > > Julie > > -- > Julie Bernauer > Yeast Structural Genomics > http://www.genomics.eu.org > > ______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html > ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
