factor.scope
Compute Allowed Changes in Adding to or Dropping from a Formula
add.scope
and drop.scope
compute those terms that can be
individually added to or dropped from a model while respecting the
hierarchy of terms.
 Keywords
 models
Usage
add.scope(terms1, terms2)
drop.scope(terms1, terms2)
factor.scope(factor, scope)
Arguments
 terms1
 the terms or formula for the base model.
 terms2
 the terms or formula for the upper (
add.scope
) or lower (drop.scope
) scope. If missing fordrop.scope
it is taken to be the null formula, so all terms (except any intercept) are candidates to be dropped.  factor
 the
"factor"
attribute of the terms of the base object.  scope
 a list with one or both components
drop
andadd
giving the"factor"
attribute of the lower and upper scopes respectively.
Details
factor.scope
is not intended to be called directly by users.
Value

For
add.scope
and drop.scope
a character vector of
terms labels. For factor.scope
, a list with components
drop
and add
, character vectors of terms labels.
See Also
Examples
library(stats)
add.scope( ~ a + b + c + a:b, ~ (a + b + c)^3)
# [1] "a:c" "b:c"
drop.scope( ~ a + b + c + a:b)
# [1] "c" "a:b"
Community examples
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