F Duan wrote: > Dear All, > > > > I have a data frame with n columns: X1, X2, ., Xn. Now I want to create a > new column: if X1 = X2 = . = Xn, the value is 1; Otherwise, the value is 0. > > > > How to do that in a quick way instead of doing (n choose 2) comparisons? > Assuming that the Xs are numeric, and your data frame is named data.df:
data.df$newcol<- as.numeric(apply(as.matrix(my.df),1,function(x) return(length(unique(x))==1))) Jim ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
