R/extractFormula.R

In geospt: Geostatistical Analysis and Design of Optimal Spatial Sampling Networks

assign("extractFormula",
       function(formula, data, newdata) {
         # extract y and X from data:
         m = model.frame(terms(formula), as(data, "data.frame"))
         z = model.extract(m, "response")
         if (length(z) == 0)
           stop("no response variable present in formula")
         Terms = attr(m, "terms")
         X = model.matrix(Terms, m)
         
         # extract x0 from newdata:
         terms.f = delete.response(terms(formula))
         mf.f = model.frame(terms.f, newdata) #, na.action = na.action)
         x0 = model.matrix(terms.f, mf.f)
         list(z = z, X = X, x0 = x0)
       }
)