Hi r-help-boun...@r-project.org napsal dne 23.09.2009 14:49:38:
> On Wed, Sep 23, 2009 at 07:29:30AM -0500, Peng Yu wrote: > > On Wed, Sep 23, 2009 at 1:24 AM, Peter Dalgaard > > <p.dalga...@biostat.ku.dk> wrote: > > > Peng Yu wrote: > > > > Is there an operation on a factor to get a subset and keep only the > > corresponding levels (see commented line below)? > > Yes, there is: call factor() on your subset: > > > a <- factor(rep(letters[1:5], 5)) > > a > [1] a b c d e a b c d e a b c d e a b c d e a b c d e > Levels: a b c d e > > b <- a[a!='b'] Or use drop argument b <- a[a!='b', drop=TRUE] regards Petr > > b > [1] a c d e a c d e a c d e a c d e a c d e > Levels: a b c d e > > factor(b) > [1] a c d e a c d e a c d e a c d e a c d e > Levels: a c d e > > > cu > Philipp > > -- > Dr. Philipp Pagel > Lehrstuhl für Genomorientierte Bioinformatik > Technische Universität München > Wissenschaftszentrum Weihenstephan > 85350 Freising, Germany > http://webclu.bio.wzw.tum.de/~pagel/ > > ______________________________________________ > 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.