model.extract {base} | R Documentation |
Returns the response, offset, subset, weights or other
special components of a model frame passed as optional arguments to
model.frame
.
model.extract(frame, component) model.offset(frame) model.response(frame)
frame |
A model frame |
component |
The name of a components to extract, such as
"weights" , "subset" |
model.offset
and
model.response
are equivalent to model.frame(,"offset")
and model.frame(,"response")
respectively.
The specified component of the model frame, usually a vector.
data(esoph) a <- model.frame(cbind(ncases,ncontrols) ~ agegp+tobgp+alcgp,data=esoph) model.extract(a,"response") all(model.extract(a,"response") == model.response(a)) a <- model.frame(ncases/(ncases+ncontrols) ~ agegp+tobgp+alcgp, data = esoph, weights = ncases+ncontrols) model.response(a) model.extract(a,"weights") a <- model.frame(cbind(ncases,ncontrols) ~ agegp, something = tobgp, data = esoph) names(a) all(model.extract(a,"something")==esoph$tobgp) # TRUE