r - combn unclasses factor variables -
update: fixed
this fixed in upcoming release of r 3.1.0. changelog:
combn(x, simplify = true)gives factor result factor inputx(previously user error).
related pr#15442
i noticed curious thing. why combn appear unclass factor variables underlying numeric values except first combination?
x <- as.factor( letters[1:3] ) combn( x , 2 ) # [,1] [,2] [,3] #[1,] "a" "1" "2" #[2,] "b" "3" "3" this doesn't occur when x character:
x <- as.character( letters[1:3] ) combn( x , 2 ) # [,1] [,2] [,3] #[1,] "a" "a" "b" #[2,] "b" "c" "c" reproducible on r64 on os x 10.7.5 , windows 7.
i think due conversion matrix done simplify parameter. if don't use get:
combn( x , 2 , simplify=false) [[1]] [1] b levels: b c [[2]] [1] c levels: b c [[3]] [1] b c levels: b c the fact first column ok due way combn works: first column specified separately , other columns changed existing matrix using [<-. consider:
m <- matrix(x,3,3) m[,2] <- sample(x) m [,1] [,2] [,3] [1,] "a" "1" "a" [2,] "b" "3" "b" [3,] "c" "2" "c" i think offending function therefore [<-.
Comments
Post a Comment