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arm (version 1.0-3)

terms: 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.bayes.

Usage

## S3 method for class 'formula':
terms(x, specials = NULL, abb = NULL, data = NULL, 
    neg.out = TRUE, keep.order = FALSE, simplify = FALSE, 
    allowDotAsName = FALSE, \dots)

Arguments

x
a formula.
specials
which functions in the formula should be marked as special in the terms object.
abb
Not implemented 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
Not implemented in R.
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, followed by the interactions, all second-order, all third-order and so on. Effects of
simplify
should the formula be expanded and simplified, the pre-1.7.0 behaviour?
...
further arguments passed to or from other methods.
allowDotAsName
normally . in a formula refers to the remaining variables contained in data. Exceptionally, . can be treated as a name for non-standard uses of formulae.

Details

This function is a revised version of terms.formula in stats package. It activates the option keep.order. It is designed for the use of bayesglm and bayesglm.hierachical where terms might need to keep unordered.

See Also

terms, terms.object, model.matrix.bayes, bayesglm.