Relevel {Epi} | R Documentation |
The levels of a factor are re-ordered so that the levels specified by
ref
is first and the others are moved down. This is useful for
contr.treatment
contrasts which take the first level as the
reference. Levels may also be combined.
Relevel(f, ref, first = TRUE, collapse="+" )
f |
An unordered factor |
ref |
The names or numbers of levels to be the first. If ref
is a list, factor levels mentioned in each list element are
combined. If the list is named the names are used as new factor levels. |
first |
Should the levels mentioned in ref come before those not? |
collapse |
String used when collapsing factor levels. |
An unordered factor.
ff <- factor( sample( letters[1:5], 100, replace=TRUE ) ) table( ff, Relevel( ff, list( AB=1:2, "Dee"=4, c(3,5) ) ) ) table( ff, rr=Relevel( ff, list( 5:4, Z=c("c","a") ), coll="-und-", first=FALSE ) )