I think this will do what you want: dframe <- read.table("your.text.file", <other args as needed> )
mat <- tapply(dframe[,3],dframe[,1:2],c) On Fri, 30 Jun 2006, Wade Wall wrote: > I have a text file that I have imported into R. It contains 3 columns and > 316940 rows. The first column is vegetation plot ID, the second species > names and the third is a cover value (numeric). I imported using the > read.table function. > > My problem is this. I need to reformat the information as a matrix, with > the first column becoming the row labels and the second the column labels > and the cover values as the matrix cell data. However, since the > read.tablefunction imported the data as an indexed data frame, I can't > use the columns > as vectors. Is there a way around this, to convert the data frame as 3 > separate vectors? I have been looking all over for a function, and my > programming skills are not great. > > Thanks in advance > > [[alternative HTML version deleted]] > > > > [ Part 3.23: "Included Message" ] > Charles C. Berry (858) 534-2098 Dept of Family/Preventive Medicine E mailto:[EMAIL PROTECTED] UC San Diego http://biostat.ucsd.edu/~cberry/ La Jolla, San Diego 92093-0717 ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html