| contrasts {base} | R Documentation |
Set and view the contrasts associated with a factor.
contrasts(x) contrasts(x) <- ctr
x |
a factor. |
ctr |
either a matrix whose columns give coefficients for
contrasts in the levels of x, or the (quoted) name of a
function which computes such matrices. |
If contrasts are not set for a factor the default functions from
options("contrasts") are used.
C,
contr.helmert,
contr.poly,
contr.sum,
contr.treatment;
glm,
aov,
lm.
example(factor) (fff <- factor(ff)) contrasts(fff) # treatment contrasts(C(fff, sum))