Mark, Give a look:
rres<-read.table(stdin(), head=T, sep=",") ID,Traversed, v2 1,5,1 1,7,1 1,8,1 2,8,2 2,11,2 2,7,2 3,11,3 3,22,3 3,16,3 aggregate(rres[c("Traversed", "v2")], list(rres$ID), sum) bests milton On Fri, May 1, 2009 at 5:07 PM, Altaweel, Mark R. <maltaw...@anl.gov> wrote: > Hi, > > I am trying to sum column information in a list with 3 instances. > > For example: > > > ID Traversed ID Traversed ID Traversed > 1 5 1 7 1 8 > 2 8 2 11 2 7 > 3 11 3 22 3 16 > > What I want to do is sum the Traversed variable across all these instances > so I can get a total value for Traversed for each ID column. So the end > output should look like the following: > > ID Traversed > 1 20 > 2 26 > 3 49 > > Basically, just sum up the columns by id. > > I am using the aggregate function, but it is not working. > > This is what I do: > agW<-aggregate(rres,rres[c('ID')],sum) //rres is the list > Error in FUN(X[[1L]], ...) : argument "INDEX" is missing, with no default > //the error message I get > > As you can see, I get the index error when I try this above. > > Can anyone help? > > Thanks in advance. > > Mark > > ______________________________________________ > 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<http://www.r-project.org/posting-guide.html> > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ 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.