And one more alternative: a1$h2 <- apply(a1,1, function(x) if (x["h1"]=="H") 1 else 0 ) -- View this message in context: http://r.789695.n4.nabble.com/Is-it-possible-to-remove-this-loop-SEC-UNCLASSIFIED-tp4635250p4635271.html Sent from the R help mailing list archive at Nabble.com.