Hi Jim, Here is one way:
# How I imagine your data might be stored l_one <- list(structure(list(key = c(2, 1, 2)), .Names = "key", row.names = c(NA, -3L), class = "data.frame")) l_two <- list(structure(list(ndx = 1:4, descr = c("this", "that", "other", "finis")), .Names = c("ndx", "descr"), row.names = c(NA, -4L), class = "data.frame")) # selecting rows from "ndx" based on "key", then # select rows from l_two based on that l_two[[1]][l_two[[1]][l_one[[1]][, "key"], "ndx"], ] I was kind of trying to guess what format your data is in. I created it as data frames (because your data looks like a data frame) contained in a list (because you said you had two lists). If your data is in a simpler format, this should be even easier. If you want a specific example for your data, an easy way is to provide us with the results of: dput(firstlist) and dput(secondlist) If they are very long you can just select the first few rows using head() or the like (e.g., dput(head(yourdata)) ). Cheers, Josh On Wed, Oct 27, 2010 at 10:53 AM, Jim Burke <j.bu...@earthlink.net> wrote: > My two lists look like below > Need an R code example that > combines the two. > > l_one > "key" > 2 > 1 > 2 > > > l_two > "ndx", "descr" > 1, "this" > 2, "that" > 3, "other" > 4, "finis" > > My goal is a new list that looks > like below. > ndx descr > 2 that > 1 this > 2 that > > Thanks, > Jim > > ______________________________________________ > 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. > -- Joshua Wiley Ph.D. Student, Health Psychology University of California, Los Angeles http://www.joshuawiley.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.