terms.formula {stats}  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
.
## S3 method for class 'formula' terms(x, specials = NULL, abb = NULL, data = NULL, neg.out = TRUE, keep.order = FALSE, simplify = FALSE, ..., allowDotAsName = FALSE)
x 
a formula. 
specials 
which functions in the formula should be marked as
special in the 
abb 
Not implemented in R. 
data 
a data frame from which the meaning of the special symbol

neg.out 
Not implemented in R. 
keep.order 
a logical value indicating whether the terms should
keep their positions. If 
simplify 
should the formula be expanded and simplified, the pre1.7.0 behaviour? 
... 
further arguments passed to or from other methods. 
allowDotAsName 
normally 
Not all of the options work in the same way that they do in S and not all are implemented.
A terms.object
object is returned. The object itself is
the reordered (unless keep.order = TRUE
) formula. In all
cases variables within an interaction term in the formula are
reordered by the ordering of the "variables"
attribute, which
is the order in which the variables occur in the formula.