Dear Guido, Try prov2<-prov[sample(1:nrow(prov),5,replace=F),] which corresponds to without replacement sampling. Best Ozgur -- View this message in context: http://r.789695.n4.nabble.com/Problem-with-sample-function-tp4632835p4632836.html Sent from the R help mailing list archive at Nabble.com.