rd_terms_by_grouping: Extract terms by grouping variables from a formula
Description
This function takes a formula as input, extracts terms that are
associated with grouping variables, and organizes them by grouping variable.
Usage
rd_terms_by_grouping(formula)
Value
a named list of one-sided formulas, where each name corresponds to
a grouping variable and the formula contains all terms associated
with that grouping variable.
Arguments
- formula
a formula object