strsplit can split by separators and strapply in the gsubfn package can split by content.
On Mon, Nov 9, 2009 at 6:40 PM, <bill.hopk...@level3.com> wrote: > Full_Name: William E. Hopkins > Version: 2.9.0 > OS: Windows XP > Submission from: (NULL) (209.244.4.106) > > > textConnection() has quadratic performance. > > A function I wrote was taking outrageous amount of time to execute on a large > character vector (small test set was used for functional development). I > created > a test harness to execute the function and gather stats (system.time) for > various dataset sizes (datasets generated by sample() of very large set). If I > used textConnection() to provide input to read.csv(), the performance was > quadratic with dataset size. However, if I had the function write the > character > vector to a temp file then read the data back in via read.csv, the performance > was linear. > > The reason for using a textConnection() was that the character vector was > within > a data frame read in via read.csv. The character vector (URLs) needed to be > parsed into separate vectors, but no mechanism exists to do that directly > (that > I know of). So, I used sub() to extract the proper pieces and put commas in > between so that I can use read.csv() to read the comma-separate strings > directly > into vectors. > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel > ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel