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 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.