You can create an empty matrix (or even array) of list elements and then assign your data frames to whichever element you want. Example:
# Allocate empty matrix... > x <- matrix(list(), nrow=2, ncol=3); # ...alternatively > x <- array(list(), dim=c(2,3)); > print(x); [,1] [,2] [,3] [1,] NULL NULL NULL [2,] NULL NULL NULL To assign a data frame to one of the elements, make sure to use double bracket notation, e.g. > x[[1,1]] <- data.frame(a=1, b=2:4); > x[[1,2]] <- data.frame(c=2:3); > x[[2,3]] <- data.frame(x=1, y=2:4); > print(x); [,1] [,2] [,3] [1,] List,2 List,1 NULL [2,] NULL NULL List,2 Same is needed to extract an element, e.g. > str(x[[2,3]]); 'data.frame': 3 obs. of 2 variables: $ x: num 1 1 1 $ y: int 2 3 4 Compare with: > str(x[2,3]); List of 1 $ :'data.frame': 3 obs. of 2 variables: ..$ x: num [1:3] 1 1 1 ..$ y: int [1:3] 2 3 4 > str(x[1,]); List of 3 $ :'data.frame': 3 obs. of 2 variables: ..$ a: num [1:3] 1 1 1 ..$ b: int [1:3] 2 3 4 $ :'data.frame': 2 obs. of 1 variable: ..$ c: int [1:2] 2 3 $ : NULL My $.02 /Henrik On Mon, Sep 13, 2010 at 11:18 PM, Jeff Newmiller <jdnew...@dcn.davis.ca.us> wrote: > raje...@cse.iitm.ac.in wrote: >> >> Hi, >> >> I create several dataframes in a nested loop and would like to maintain >> them in a matrix form with each dataframe represented by the row and the >> column. How can I do this? >> > > You can't, at least as you describe it. > > However, you can add a column for "row ID" and a column for "column ID" to > each of your result data frames and "rbind" them together. > > It is also possible to create lists of lists... but I believe the single > augmented dataframe will be way more useful in the long run. > > ______________________________________________ > 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.