Infrastructure for extended formulas in R with multiple parts on the right-hand side and/or multiple responses on the left-hand side.
Extended Formula with 2 right-hand sides for mtcars data:
library("Formula")
F <- Formula(log(mpg) ~ disp | factor(vs))
mf <- model.frame(F, data = head(mtcars, 3))Extract response and both regressor matrices from model frame:
model.response(mf)
#> Mazda RX4 Mazda RX4 Wag Datsun 710
#> 3.044522 3.044522 3.126761
model.matrix(F, data = mf, rhs = 1)
#> (Intercept) disp
#> Mazda RX4 1 160
#> Mazda RX4 Wag 1 160
#> Datsun 710 1 108
#> attr(,"assign")
#> [1] 0 1
model.matrix(F, data = mf, rhs = 2)
#> (Intercept) factor(vs)1
#> Mazda RX4 1 0
#> Mazda RX4 Wag 1 0
#> Datsun 710 1 1
#> attr(,"assign")
#> [1] 0 1
#> attr(,"contrasts")
#> attr(,"contrasts")$`factor(vs)`
#> [1] "contr.treatment"