R: A function to construct a terms object from a formula.

terms.formula {base}

R Documentation

A function to construct a terms object from a formula.

Description

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.

Usage

terms.formula(x, specials=NULL, abb=NULL, data=NULL, neg.out=TRUE,
              keep.order=FALSE, ...)

Arguments

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 and 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.

...

further arguments passed to or from other methods.

Details

Not all of the options work in the same way that they do in S and not all are implemented.

Value