How can one or more levels be removed from a factor of a data frame. There was a similar post on how to do this when a factor meets some criterion (e.g. <= 2), but I can¹t seem to get that solution to work. Here, I simply want to drop some levels. [[alternative HTML version deleted]]
Henrik Wahren wrote:> > How can one or more levels be removed from a factor of a data frame. There > was a similar post on how to do this when a factor meets some criterion > (e.g. <= 2), but I can?t seem to get that solution to work. > Here, I simply want to drop some levels. > >Simply call factor again on the reduced set a = factor(c("a","b","b","b")) a[-1] factor(a[-1]) If a is in a data frame, replace a by by df$a. Dieter -- View this message in context: http://old.nabble.com/Removing-levels-of-a-factor-tp26296742p26297130.html Sent from the R help mailing list archive at Nabble.com.
Dieter Menne wrote:> > > Henrik Wahren wrote: >> How can one or more levels be removed from a factor of a data frame. There >> was a similar post on how to do this when a factor meets some criterion >> (e.g. <= 2), but I can?t seem to get that solution to work. >> Here, I simply want to drop some levels. >> >> > > Simply call factor again on the reduced set > > a = factor(c("a","b","b","b")) > a[-1] > factor(a[-1]) > > If a is in a data frame, replace a by by df$a. >or a[-1, drop=TRUE] Uwe Ligges> Dieter