read.table's colClasses= argument can take a "NULL" for those columns that you want ignored. Also see the skip= argument. ?read.table .
The sqldf package can read a subset of rows and columns (actually any sql operation) from a file larger than R can otherwise handle. It will automatically set up a temporary SQLite database for you, load the file into the database without going through R and extract just the data you want into R and then automatically delete the database. All this can be done in 2 lines of code. See example 6 on the home page: http://sqldf.googlecode.com On Thu, Feb 28, 2008 at 12:03 AM, Jorge Iván Vélez <[EMAIL PROTECTED]> wrote: > Dear R-list, > > Does somebody know how can I read a HUGE data set using R? It is a hapmap > data set (txt format) which is around 4GB. After read it, I need to delete > some specific rows and columns. I'm running R 2.6.2 patched over XP SP2 > using a 2.4 GHz Core 2-Duo processor and 4GB RAM. Any suggestion would be > appreciated. > > Thanks in advance, > > Jorge > > [[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.