On 20-02-2012, at 10:40, Nerak wrote: > Hi all, > I have a question concerning using several conditions in an ifelse function > used as the function in apply. > I want to create a new value with the function ifelse ‘ object which can be > coerced to logical mode “test[n,] >1 & test[n-1,]==0” > With n I mean the row. I don’t know how I could do this without a loop. I > want to avoid the usage of loops and was thinking about apply. This was what > I was thinking about: > > test<-data.frame(C=c(0,0,0,0,5,2,0,0,0,15,12,10,6,0,0,0),B=c(0,0,0,0,9,6,2,0,0,24,20,16,2,0,0,0),F=c(0,0,0,0,6,5,1,0,0,18,16,12,10,5,1,0)) > > test.b<-test[-(nrow(test)),] > test.2b<-rbind(0,test.b) > result<-as.data.frame(apply(test,M=2,function(x)ifelse((test>1&test.2b==0),1,0))) >
You are not using the argument "x" in the ifelse. For every column (you have 3) you are evaluating the ifelse condition. > But I get 3 times the amount of rows than that I want… > what I should achieve: > test.result<-data.frame(C=c(0,0,0,0,1,0,0,0,0,1,0,0,0,0,0,0),B=c(0,0,0,0,1,0,0,0,0,1,0,0,0,0,0,0),F=c(0,0,0,0,1,0,0,0,0,1,0,0,0,0,0,0)) > > Has someone a suggestions about what I’m doing wrong? Simplify. You don't need apply. This'll do it result <- ifelse((test>1) & (test.2b==0),1,0) Berend ______________________________________________ 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.
