The help for model.frame says
Only variables whose type is raw, logical, integer, real, complex
or character can be included in a model frame: this includes
classed variables such as factors (whose underlying type is
integer), but excludes lists.
Some S4 objects are of one of
Hi,
I have very carefully developed several S4 classes that describe
censored water-quality data. I have routines for them that will support
their use in data.frames and so forth. I have run into a problem when I
try to use the S4 class as the response variable in a formula and try to
extract
