Hi, thanks for response it's work perfect. Yes 't' is not good wariable it will be 'test', my wrong. Best Marcin M. -- View this message in context: http://r.789695.n4.nabble.com/Removing-all-duplicate-row-except-by-one-tp3736949p3738132.html Sent from the R help mailing list archive at Nabble.com.