interaction {base} | R Documentation |
interaction
computes a factor which represents the interaction
of the given factors. The result of interaction
is always unordered.
interaction(..., drop=FALSE)
... |
The factors for which interaction is to be computed. |
drop |
If drop is TRUE , empty factor levels
are dropped from the result. The default is to retain all
factor levels. |
A factor which represents the interaction of the given factors.
a <- gl(2, 2, 8) b <- gl(2, 4, 8) interaction(a, b)