Hi, I could not use 'exlcude=' option in factor() to exclude a level from a existing factor. x is a factor:> x[1] a b c Levels: a b c> factor(x,exclude="c")[1] a b c Levels: a b c Warning message: NAs introduced by coercion However, "c" is not coded as NA. The following does not work either:> factor(x,exclude=factor("c",levels=c("a","b","c")))[1] a b c Levels: a b c What's wrong with my codes? Thanks for any help Qiong Yang
Qiong Yang wrote:> Hi, > > I could not use 'exlcude=' option in factor() > to exclude a level from a existing factor. > > x is a factor: > > >>x > > [1] a b c > Levels: a b c > > >>factor(x,exclude="c") > > [1] a b c > Levels: a b c > Warning message: > NAs introduced by coercion > > However, "c" is not coded as NA. > > The following does not work either: > > >>factor(x,exclude=factor("c",levels=c("a","b","c"))) > > [1] a b c > Levels: a b c > > > What's wrong with my codes? >I think you want: x <- factor(letters[1:3]) factor(as.character(x), exclude = "c") HTH, --sundar
Qiong Yang wrote:> Hi, > > I could not use 'exlcude=' option in factor() > to exclude a level from a existing factor. > > x is a factor: > > >>x > > [1] a b c > Levels: a b c > > >>factor(x,exclude="c") > > [1] a b c > Levels: a b c > Warning message: > NAs introduced by coercion > > However, "c" is not coded as NA. > > The following does not work either: > > >>factor(x,exclude=factor("c",levels=c("a","b","c"))) > > [1] a b c > Levels: a b c > > > What's wrong with my codes?factor(x, levels=letters[1:2]) Uwe Ligges> Thanks for any help > > Qiong Yang > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html