| 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, or a single list giving those factors. |
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.
The levels are labelled as the levels of the individual factors joined
by ..
Chambers, J. M. and Hastie, T. J. (1992) Statistical Models in S. Wadsworth & Brooks/Cole.
a <- gl(2, 2, 8) b <- gl(2, 4, 8) interaction(a, b)