Functions to Check the Type of Variables passed to Model Frames
.checkMFClasses checks if the variables used in a predict
method agree in type with those used for fitting.
.MFclass categorizes variables for this purpose.
.checkMFClasses(cl, m, ordNotOK = FALSE) .MFclass(x) .getXlevels(Terms, m)
a character vector of class descriptions to match.
a model frame.
any R object.
logical: are ordered factors different?
For applications involving
model.matrix such as linear models
we do not need to differentiate between ordered factors and factors as
although these affect the coding, the coding used in the fit is
already recorded and imposed during prediction. However, other
applications may treat ordered factors differently:
rpart does, for example.
.MFclass returns a character string, one of
(a numeric matrix with a number of columns appended) or
.getXlevels returns a named character vector, or