On 9/24/2008 10:06 AM, Doran, Harold wrote: > Say I have the following data: > > testDat <- data.frame(A = c(1,NA,3), B = c(NA, NA, 3)) > >> testDat > A B > 1 1 NA > 2 NA NA > 3 3 3 > > rowsums() with na.rm=TRUE generates the following, which is not desired: > >> rowSums(testDat[, c('A', 'B')], na.rm=T) > [1] 1 0 6 > > rowsums() with na.rm=F generates the following, which is also not > desired: > > >> rowSums(testDat[, c('A', 'B')], na.rm=F) > [1] NA NA 6 > > I see why this occurs, but what I hope to have returned would be: > [1] 1 NA 6 > > To get what I want I could do the following, but normally my ideas are > bad ideas and there are codified and proper ways to do things. > > rr <- numeric(nrow(testDat)) > for(i in 1:nrow(testDat)) rr[i] <- if(all(is.na(testDat[i,]))) NA else > sum(testDat[i,], na.rm=T) > >> rr > [1] 1 NA 6 > > Is there a "proper" way to do this? In my real data, nrow is over > 100,000
I don't know if it is "proper", but here is a slightly different way that I find easier to read: apply(testDat, 1, function(x){ ifelse(all(is.na(x)), NA, sum(x, na.rm=TRUE)) }) [1] 1 NA 6 hope this helps, Chuck > Thanks, > Harold > >> sessionInfo() > R version 2.7.2 (2008-08-25) > i386-pc-mingw32 > > locale: > LC_COLLATE=English_United States.1252;LC_CTYPE=English_United > States.1252;LC_MONETARY=English_United > States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252 > > attached base packages: > [1] stats graphics grDevices utils datasets methods base > > > other attached packages: > [1] MiscPsycho_1.2 lattice_0.17-13 statmod_1.3.6 > > loaded via a namespace (and not attached): > [1] grid_2.7.2 > > ______________________________________________ > 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. -- Chuck Cleland, Ph.D. NDRI, Inc. (www.ndri.org) 71 West 23rd Street, 8th floor New York, NY 10010 tel: (212) 845-4495 (Tu, Th) tel: (732) 512-0171 (M, W, F) fax: (917) 438-0894 ______________________________________________ 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.