On Sat, Apr 21, 2012 at 3:28 PM, Max Kuhn <mxk...@gmail.com> wrote: > For a package, I need to write a csv version of a data set to an R > object. Right now, I use: > > out <- capture.output( > write.table(x, > sep = ",", > na = "?", > file = "", > quote = FALSE, > row.names = FALSE, > col.names = FALSE)) > > To me, this is fairly slow; 131 seconds for a data frame with 8100 > rows and 1400 columns. > > The data will be in a data frame; I know write.table() would be faster > with a matrix. I was looking into converting the data frame to a > character matrix using as.matrix() or, better yet, format() prior to > the call above. However, I'm not sure what an appropriate value of > 'digits' should be so that the character version of numeric data has > acceptable fidelity. > > I also tried using a text connection and sink() as shown in > ?textConnection but there was no speedup. >
You could try a loop over each row, and use 'paste' to join each element in a row by commas. Then use 'paste' again to join everything you've got (a vector of rows) by a '\n' character. something like: paste(apply(x,1,paste,collapse=","),collapse="\n") # untested you probably also want to stick a final \n on it. Is it faster? I don't know! Barry ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
