Hi Pele, I think this should work
file1$state.sum <- rowSums(file2[file1$state,6:10],0) On Thu, Sep 23, 2010 at 7:46 PM, Steve Lianoglou < mailinglist.honey...@gmail.com> wrote: > Hi Pele, > > On Wed, Sep 22, 2010 at 12:40 PM, Pele <drdi...@yahoo.com> wrote: > > > > Hi David - thanks for your suggestion, but I am trying to avoid doing any > > merging and sorting for this step because the real file I will be working > > with has about 20 million records. If I can get this loop or something > > similar to work will be good enough. > > If that's the case, you might consider looking at the sqldf or > data.table packages. > > They both implement data.frame-like objects, but can do subsetting > (and merging) rather quickly since they implement indexes over "keys" > (columns) of the respective data.frame(s). > > Subsetting "normal" data.frames in this scenario you describe involves > a linear search for every query through the column(s) you are querying > against, which can get slow as the size of your data.frames get large. > > -steve > > -- > Steve Lianoglou > Graduate Student: Computational Systems Biology > | Memorial Sloan-Kettering Cancer Center > | Weill Medical College of Cornell University > Contact Info: > http://cbio.mskcc.org/~lianos/contact<http://cbio.mskcc.org/%7Elianos/contact> > > ______________________________________________ > 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. > [[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.
