Create a data frame with just the variables in the formula in
a lm object.
This is comparable to model.matrix or model.frame except that factors,
polynomials, transformations, etc. are not expanded.
Usage
model.data(lmobj, lhs = FALSE)
Value
A data frame containing each of the variables referenced in the model formula.
Boolean indicator of whether or not to include the variable(s)
on the left-hand side of the model formula.
Author
Russell V. Lenth
Details
This is an easy-to-use substitute for get_all_vars.
The formula, data, and subset arguments, if present in
lmobj's call, affect the result appropriately.
References
Lenth RV (2009) ``Response-Surface Methods in R, Using rsm'',
Journal of Statistical Software, 32(7), 1--17.
tools:::Rd_expr_doi("10.18637/jss.v032.i07")