interaction {base}

R Documentation

Compute Factor Interactions

Description

interaction computes a factor which represents the interaction of the given factors. The result of interaction is always unordered.

Usage

interaction(..., drop=FALSE)

Arguments

...	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.

Value

A factor which represents the interaction of the given factors.

References

Chambers, J. M. and Hastie, T. J. (1992) Statistical Models in S. Wadsworth \& Brooks/Cole.

See Also

factor.

Examples

a <- gl(2, 2, 8)
b <- gl(2, 4, 8)
interaction(a, b)

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