Hi all, I have two numeric variables that form combinations in a matched sample. Let's say I have five levels of x and y. What I am seeking to create is a factor variable that ignores the order of x and y, i.e., the factor should indicate x=1, y=5, as the same factor as x=5, y=1. Obviously, this becomes increasingly cumbersome to do by hand as the number of levels increases.
f<-1:5 x<-sample(f,100,replace=T) y<-sample(f,100,replace=T) d<-matrix(cbind(x,y),ncol=2) #A working solution is to remove the order, multiply one column by a scaling constant, add the second column, and create the factor for this numeric value. However, I was wondering whether there is less awkward, more direct way to do this. i<-apply(t(apply(d,1,function(x) sort(x))),1,function(y) 10*y[1]+y[2]) i<-factor(i) i Thanks for your help, Daniel -- View this message in context: http://r.789695.n4.nabble.com/create-a-factor-variable-from-two-numeric-variables-when-order-is-irrelevant-tp3631318p3631318.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
