How about:
X<-as.matrix(yourframe) apply(X,2, '==',X[,1])%*%rep(1,ncol(X)) == ncol(x) avoiding the rowwise apply overhead? Cheers, Bert Gunter Non-Clinical Biostatistics Genentech MS: 240B Phone: 650-467-7374 "The business of the statistician is to catalyze the scientific learning process." -- George E.P. Box 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? > > > > Thank you, > > > > Frank > > [[alternative HTML version deleted]] > > ______________________________________________ > [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 ______________________________________________ [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
