> Cat=c('a','a','a','b','b','b','a','a','b') # Categorical variable > C1=vector(length=length(Cat)) # New vector for numeric values > > # Cycle through each column and set C1 to corresponding value of Cat. > for(i in 1:length(C1)){ > if(Cat[i]=='a') C1[i]=-1 else C1[i]=1 > } > > C1 > [1] -1 -1 -1 1 1 1 -1 -1 1 > Cat > [1] "a" "a" "a" "b" "b" "b" "a" "a" "b" > > how about:
Cat<-c('a','a','a','b','b','b','a','a','b') c1<- -2*(Cat=="a")+1 -=-=- ... Time is an illusion, lunchtime doubly so. (Ford Prefect) ______________________________________________ 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.