terms.formula {base} | R Documentation |
This function takes a formula and some optional arguments and
constructs a terms object. The terms object can then be used to
construct a model.matrix
.
terms.formula(x, specials=NULL, abb=NULL, data=NULL, neg.out=TRUE, keep.order=FALSE)
x |
A formula. |
specials |
What functions in the formula should be marked as special in the terms object. |
abb |
Unused in R. |
data |
A data frame from which the meaning of the special symbol
. can be inferred. It is unused if there is no . in
the formula. |
neg.out |
TRUE if terms with a minus, - should be removed.
If FALSE these are kept in an indicate a negative order (for fractionate?). |
keep.order |
A logical value indicating whether the terms should keep their positions. If FALSE the terms are reordered so that main effects come first. |
Not all of the options work in the same way that they do in S and not all are implemented.
A terms
object is returned.