TITLE(interaction @@ Factor Interactions)
USAGE(
interaction(fac1, fac2, data.order=true)
)
ARGUMENTS(
ARG(fac1 @@ the name of the first factor.)
ARG(fac2 @@ the name of the second factor.)
ARG(data.order @@ controls the order in which the factor level
names are stored.)
)
DESCRIPTION(
LANG(interaction) returns a new factor that has a level
for each combination of the factors LANG(fac1) and LANG(fac2).
If LANG(true), it is the order that the factor levels first appear
in the vectors LANG(fac1) and LANG(fac2), otherwise alphabetical.
)
