You could use lists of lists, and index them with vectors. a <- list() a[[1]] <- list() a[[2]] <- list() a[[c(1,1)]] <- g11 a[[c(1,2)]] <- g12 a[[c(2,1)]] <- g21 a[[c(2,2)]] <- g22 print(a[[c(2,1)]])
but this seems like an inefficient use of memory because your indexed data is stored more compactly than the graph object is. I would index the data and generate the graph object on the fly when I wanted to see it. --------------------------------------------------------------------------- Jeff Newmiller The ..... ..... Go Live... DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live Go... Live: OO#.. Dead: OO#.. Playing Research Engineer (Solar/Batteries O.O#. #.O#. with /Software/Embedded Controllers) .OO#. .OO#. rocks...1k --------------------------------------------------------------------------- Sent from my phone. Please excuse my brevity. jpm miao <miao...@gmail.com> wrote: >Hi, > >I have a few graph objects created by some graphic package (say, >ggplot2, >which I use frequently). Because of the existent relation between the >graphs, I'd like to index them in two dimensions as p[1,1], p[1,2], >p[2,1], >p[2,2] for convenience. > >To my knowledge, the only data type capable of storing graph objects >(and >any R object) is list, but unfortunately it is available in only one >dimension. Could the graphs be stored in any two-dimensional data type? > > One remedy that comes to my mind is to build a function f so that >f(1,1)=1 >f(1,2)=2 >f(2,1)=3 >f(2,2)=4 >With functions f and f^{-1} (inverse function of f) , the >two-dimensional >indices could be mapped to and from a set of one-dimensional indices, >and >the functions are exactly the way R numbers elements in a matrix. Does >R >have this built-in function for a m by n matrix or more generally, >m*n*p >array? (I know this function is easy to write, but just want to make >sure >whether it exists already) > > Thanks, > >Miao > > [[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. ______________________________________________ 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.