> A <- matrix(-4:4, ncol=3) > A [,1] [,2] [,3] [1,] -4 -1 2 [2,] -3 0 3 [3,] -2 1 4 > Apos <- A; Apos[A <= 0] <- NA; > Apos [,1] [,2] [,3] [1,] NA NA 2 [2,] NA NA 3 [3,] NA 1 4 > Aneg <- A; Aneg[A >= 0] <- NA > Aneg [,1] [,2] [,3] [1,] -4 -1 NA [2,] -3 NA NA [3,] -2 NA NA
/Henrik On Fri, Oct 31, 2008 at 7:59 AM, Diogo André Alagador <[EMAIL PROTECTED]> wrote: > Dear all, > > I have a matrix with positive and negative values. > >From this I would like to produce 2 matrices: > 1st - retaining positives and putting NA in other positions > 2nd - retaining negatives and putting NA in other positions > > and then apply rowMeans for both. > > I am trying to use the function ifelse in the exemplified form: > ifelse(A>0,A,NA) > but by putting A as a 2nd parameter it changes dimensions of the original > object. > > I wonder if I can do this, as it seems not to difficult. > > thanks in advance > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.