1st of all Dr Utz, thanks for your recent pubs on regional differences between the piedmont and coastal plain streams.
and to add to Daniels post (giving your binary yes/no): df<-merge(x,y,all.x=T,all.y=F) df["exceed"] <- ifelse(df$Q>df$Threshold_Q , 1, 0) ## now look at df df Daniel Malter wrote: > > For example, you can merge the two data frames and do a direct comparison: > > df<-merge(x,y,all.x=T,all.y=F) > df > df$Q>df$Threshold_Q > > HTH, > Daniel > > > Ryan Utz-2 wrote: >> >> Hi all, >> >> I have two datasets, one that represents a long-term time series and one >> that represents summary data for the time series. It looks something like >> this: >> >> x<-data.frame(Year=c(2001,2001,2001,2001,2001,2001,2002,2002,2002,2002,2002,2002), >> Month=c(1,1,1,2,2,2),Q=c(5,5,5,6,6,6,3,3,3,4,4,5)) >> y<-data.frame(Year=c(2001,2001,2002,2002),Month=c(1,2,1,2),Threshold_Q=c(5,5,4,4)) >> >> What I'd like to do is link the Year and Month fields in both dataframes >> then determine if Q exceeds Q_Threshold (by noting it with something like >> 1 >> or 0 in a new field in the dataframe x). >> >> If I were doing this in the more-familiar-to-me Matlab, I'd just write a >> pair of nested for-loops. But as we know, this won't fly in R. I've tried >> reading the help pages and seeking for solutions on the net, with no luck >> (I'm relatively new to R and the help pages are still a bit opaque to >> me). >> It seems like the functions "apply" or "lapply" are key, but I can't make >> sense of their syntax. >> >> Any advice/help?!? >> >> Many thanks, >> Ryan >> >> -- >> >> Ryan Utz, Ph.D. >> Aquatic Ecologist/STREON Scientist >> National Ecological Observatory Network >> >> Home/Cell: (724) 272-7769 >> Work: (720) 746-4844 ext. 2488 >> >> [[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. >> > -- View this message in context: http://r.789695.n4.nabble.com/Linking-2-columns-in-2-databases-and-applying-a-function-tp3617710p3617861.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
