On Thursday, May 07, 2009 7:45 PM, David Freedman wrote: > ...how about: > d=data[order(data$ID,-data$Type),] > d[!duplicated(d$ID),] Does the "-data$Type" argument to the order function work? -- David ----------------------------------------------------- David Huffer, Ph.D. Senior Statistician CSOSA/Washington, DC david.huffer at csosa.gov