A helper function for extracting response values, observation weights, and
offsets from a dataset. It is designed for use in the extract_model_data
function of custom reference model objects (see init_refmodel()).
y_wobs_offs(newdata, wrhs = NULL, orhs = NULL, resp_form)The data.frame from which at least the response values
should be extracted.
Either a right-hand side formula consisting only of the variable
in newdata containing the weights, NULL (for using a vector of ones),
or directly the numeric vector of observation weights.
Either a right-hand side formula consisting only of the variable
in newdata containing the offsets, NULL (for using a vector of zeros),
or directly the numeric vector of offsets.
If this is a formula, then the second element of this
formula (if the formula is a standard formula with both left-hand and
right-hand side, then its second element is the left-hand side; if the
formula is a right-hand side formula, then its second element is the
right-hand side) will be extracted from newdata (so resp_form may be
either a standard formula or a right-hand side formula, but in the latter
case, the right-hand side should consist only of the response variable). In
all other cases, NULL will be returned for element y of the output
list.
A list with elements y, weights, and offset, each being a
numeric vector containing the data for the response, the observation
weights, and the offsets, respectively. An exception is that y may also
be NULL (depending on argument resp_form), a non-numeric vector, or a
factor.
# For an example, see `?init_refmodel`.