Then there's something missing in what you tell us.
# this is an awkward and inefficient way of constructing a data frame city<-data.frame(city="Barcelona",cod=1) city<-rbind(city,data.frame(city="Madrid",cod=2)) city<-rbind(city,data.frame(city="Lisbon",cod=3)) city<-rbind(city,data.frame(city="Milan",cod=4)) city<-rbind(city,data.frame(city="London",cod=5)) travel<-data.frame(pos=1,Source=1,Destine=2) travel<-rbind(travel,data.frame(pos=1,Source=1,Destine=3)) travel<-rbind(travel,data.frame(pos=2,Source=3,Destine=4)) travel<-rbind(travel,data.frame(pos=3,Source=2,Destine=4)) travel<-rbind(travel,data.frame(pos=4,Source=1,Destine=3)) temp <- merge(travel, city, by.x="Source", by.y="cod") result <- merge(temp, city, by.x="Destine", by.y="cod") > temp Source pos Destine city 1 1 1 2 Barcelona 2 1 1 3 Barcelona 3 1 4 3 Barcelona 4 2 3 4 Madrid 5 3 2 4 Lisbon > result Destine Source pos city.x city.y 1 2 1 1 Barcelona Madrid 2 3 1 1 Barcelona Lisbon 3 3 1 4 Barcelona Lisbon 4 4 2 3 Madrid Milan 5 4 3 2 Lisbon Milan On Mon, Mar 26, 2012 at 11:08 AM, MSousa <ricardosousa2...@clix.pt> wrote: > thanks for the reply, > > But does not the results I need. What is confusing is that when making > the first merge it gives only two cities when it should take three > > > travel<-data.frame(pos=1,Source=1,Destine=2) > travel<-rbind(travel,data.frame(pos=1,*Source=1*,Destine=3)) > travel<-rbind(travel,data.frame(pos=2,*Source=3*,Destine=4)) > travel<-rbind(travel,data.frame(pos=3,*Source=2*,Destine=4)) > travel<-rbind(travel,data.frame(pos=4,*Source=1*,Destine=3)) > > temp1 <- merge(travel, city, by.x='Source', by.y='cod') >>temp1 () > Source pos Destine city > 1 *1* 1 2 Barcelona > 2 1 1 3 Barcelona > 3 1 4 3 Barcelona > 4 *2 * 3 4 Madrid > -- Sarah Goslee http://www.functionaldiversity.org ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
