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 |
specials |
which functions in the formula should be marked as
special in the |
abb |
Not implemented in R; deprecated. |
data |
a data frame from which the meaning of the special symbol
|
neg.out |
Not implemented in R; deprecated. |
keep.order |
a logical value indicating whether the terms should
keep their positions. By default, when |
simplify |
should the formula be expanded and simplified, the pre-1.7.0 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 is returned. It is the re-ordered formula (unless
keep.order = TRUE
) with several attributes
, see
terms.object
for details. In all
cases variables within an interaction term in the formula are
re-ordered by the ordering of the "variables"
attribute, which
is the order in which the variables occur in the formula.
terms
, terms.object
, also for examples.