Hi Hans, try this ...
mat <- as.data.frame(cbind(Plant,Value1,Value2)) mat$Plant1 <- ifelse(is.na(mat$Plant), "A", "B") Cheers Andrew On Tue, Dec 05, 2006 at 04:33:15PM +0100, Hans-Juergen Eickelmann wrote: > > Dear R-community, > > my data set looks like 'mat' below. > > Plant<-c(NA,1,1,1,NA,NA,NA,NA,NA,1); > Value1<-rnorm(1:10); > Value2<-rnorm(1:10); > mat<-cbind(Plant,Value1,Value2); > I receive data from two different sites. > One site is identified by an interger number, the other site has no data in > column Plant=NA. > > My pb: > > I'm trying to assign labels "A" or "B" to these 2 sites into a new column, > but my if(){} else{} statement fails with the following statement: > Error in if (is.na(mat$Plant == TRUE)) { : > argument is of length zero > > if(is.na(mat$Plant==TRUE)){mat$Plant1="A"} else{mat$Plant1="B"}; > > I looked through the avail doc and R-help for some time but wasn't able to > fix the pb. > > Thx Hans > > ______________________________________________ > R-help@stat.math.ethz.ch 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. -- Andrew Robinson Department of Mathematics and Statistics Tel: +61-3-8344-9763 University of Melbourne, VIC 3010 Australia Fax: +61-3-8344-4599 http://www.ms.unimelb.edu.au/~andrewpr http://blogs.mbs.edu/fishing-in-the-bay/ ______________________________________________ R-help@stat.math.ethz.ch 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.