Jörg To add a level you could:
x <- factor(c("xyz1", "abc1", "xyz2", "abc2")) x1 <- factor(x, levels=c(levels(x), 'fgh')) summary(x) abc1 abc2 xyz1 xyz2 1 1 1 1 summary(x1) abc1 abc2 xyz1 xyz2 fgh 1 1 1 1 0 For the others, I tend to convert to a character, make the changes and convert back to a factor - but there is probably a better way. HTH .... Peter Alspach. > -----Original Message----- > From: r-help-boun...@r-project.org > [mailto:r-help-boun...@r-project.org] On Behalf Of Jörg Groß > Sent: Tuesday, 16 December 2008 3:26 p.m. > To: r-help@r-project.org > Subject: [R] renaming factor-labels / add factors etc. > > Hi, > > how can I change a defined factor-variable? > Like adding levels, renaming existing levels or merge several > levels of a factor to one level? > > > > For example; following factor-variable is given: > > x <- factor(c("xyz1", "abc1", "xyz2", "abc2")) > > > How can I add the level fgh? > And how can I merge "xyz1" and "xyz2" to one level? > And how can I change the name? > > > > > Thanks for any help! > > ______________________________________________ > 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. > The contents of this e-mail are confidential and may be subject to legal privilege. If you are not the intended recipient you must not use, disseminate, distribute or reproduce all or any part of this e-mail or attachments. If you have received this e-mail in error, please notify the sender and delete all material pertaining to this e-mail. Any opinion or views expressed in this e-mail are those of the individual sender and may not represent those of The New Zealand Institute for Plant and Food Research Limited. ______________________________________________ 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.