| contrasts {base} | R Documentation |
Get and Set Contrast Matrices
Description
Set and view the contrasts associated with a factor.
Usage
contrasts(x)
contrasts(x) <- ctr
Arguments
x |
a factor. |
ctr |
either a matrix whose columns give coefficients for
contrasts in the levels of |
Details
If contrasts are not set for a factor the default functions from
options("contrasts") are used.
See Also
C,
contr.helmert,
contr.poly,
contr.sum,
contr.treatment;
glm,
aov,
lm.
Examples
example(factor)
(fff <- factor(ff))
contrasts(fff) # treatment
contrasts(C(fff, sum))