I'm trying to create a new column in my data.frame where subjects are categorized depending on values on four other columns. In any other case I would just nest a few ifelse statements, however, in this case i have 4*6*2*3=144 combinations and i get weird 'context overflow' errors. So I wonder if there is a more efficient way of doing this.
For illustrational purposes, let's say i have: x<-c(1,0,0,1,0,0,1,0,0,1) y<-c(1,3,2,3,2,1,2,3,2,3) z<-c(1,2,1,2,1,2,1,2,1,2) d<-as.data.frame(cbind(x,y,z)) and i do: d$myvar <- ifelse(d$x == 0 & d$y==1 & d$z==1 , d$myvar <- 1, ifelse(d$x == 0 & d$y==1 & d$z==2 , d$myvar <- 2, ifelse(d$x == 0 & d$y==2 & d$z==1 , d$myvar <- 3, ifelse(d$x == 0 & d$y==2 & d$z==2 , d$myvar <- 4, ifelse(d$x == 0 & d$y==3 & d$z==1 , d$myvar <- 5, ifelse(d$x == 0 & d$y==3 & d$z==2 , d$myvar <- 6, ifelse(d$x == 1 & d$y==1 & d$z==1 , d$myvar <- 7, ifelse(d$x == 1 & d$y==1 & d$z==2 , d$myvar <- 8, ifelse(d$x == 1 & d$y==2 & d$z==1 , d$myvar <- 9, ifelse(d$x == 1 & d$y==2 & d$z==2 , d$myvar <- 10, ifelse(d$x == 1 & d$y==3 & d$z==1 , d$myvar <- 11, ifelse(d$x == 1 & d$y==3 & d$z==2 , d$myvar <- 12, NA)))))))))))) Suggestions? ______________________________________________ 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.
