Thanks, David, that works too!
On Thu, Jun 25, 2009 at 10:30 AM, David Winsemius <dwinsem...@comcast.net>wrote: > > On Jun 25, 2009, at 10:24 AM, Rama Ramakrishnan wrote: > > Follow-on question: is there a way to do this for higher-dimensional (i.e. >> more than 2 dimensions) arrays? >> > > The apply method I just posted generalizes to higher dimensional arrays. > > -- > DW > > >> >> On Thu, Jun 25, 2009 at 10:17 AM, Rama Ramakrishnan <r...@alum.mit.edu >> >wrote: >> >> That works!! Very nice way to do it! Thank you, Henrique! >>> Rama Ramakrishnan >>> >>> >>> On Thu, Jun 25, 2009 at 10:11 AM, Henrique Dallazuanna <www...@gmail.com >>> >wrote: >>> >>> Try this: >>>> >>>> y$values <- diag(x[y$ltrs, y$mnths]) >>>> >>>> On Thu, Jun 25, 2009 at 11:02 AM, Rama Ramakrishnan <r...@alum.mit.edu >>>> >wrote: >>>> >>>> Dear R-Users, >>>>> I need to lookup values from a 2-d table using the row names and column >>>>> names as indices. I was wondering if there's a way to do this without >>>>> an >>>>> explicit loop. >>>>> >>>>> Example: >>>>> #x is the 2-d table that holds the values >>>>> >>>>> x <- matrix(rnorm(26*12),nrow=26) >>>>> >>>>> rownames(x) <- letters >>>>> >>>>> colnames(x) <- month.name >>>>> >>>>> >>>>> #y is a data frame that has the "keys" I want to use as indices into x >>>>> >>>>> y <- data.frame(ltrs=sample(letters,5),mnths=sample(month.name >>>>> ,5),values=0) >>>>> >>>>> >>>>> #I want to fill in the "values" column using the "ltrs" and "mnths" >>>>> columns >>>>> as keys to look up >>>>> >>>>> snip >>>> >>> >>> >>> >> [[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. >> > > David Winsemius, MD > Heritage Laboratories > West Hartford, CT > > [[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.
