The left~right side of the model (excluding groups)
lhs
The call for the left hand side
rhs
The call for the right hand side (excluding groups)
groups
The call for the groups
groupFormula
A formula form of the groups
env
The original formula's environment
Arguments
form
the formula to extract into its parts
require.groups
is it an error not to have groups?
require.two.sided
is it an error to have a one-sided
formula?
Details
This function extracts the left hand side (lhs), right hand
side (rhs), groups (groups and as a formula,
grpFormula), the environment (env, and the original
left/right hand side of the model (model).
This function borrows heavily from the parseGroupFormula
function in the doBy package.
See Also
Other Formula parsing:
findOperator(),
formula.parseFormula()
parseFormula("a~b", require.groups=FALSE)
# parseFormula("a~b", require.groups=TRUE) # This is an errorparseFormula("a~b|c")
parseFormula("a~b|c")$groups