| ### Test calling drop1.default() "deep down" -- via |
| ### correct formula environment |
| |
| library(stats) |
| if(!require(MASS)) q() |
| |
| regr <- function(formula, data, ...) |
| { |
| lform <- formula(formula) |
| d1 <- data |
| i.polr(lform, d1, ...) |
| } |
| |
| i.polr <- function(form, data, ...) |
| { |
| lfo <- form |
| d2 <- data |
| environment(lfo) <- environment() |
| lreg <- polr(lfo, data = d2, ...) |
| do.drop(lreg, lreg1$coef, ltesttype = "Chisq") |
| } |
| |
| do.drop <- function(lreg, lcoeftab, ltesttype) |
| drop1(lreg, test = ltesttype, scope = terms(lreg), trace = FALSE) |
| |
| m <- polr(Sat ~ Infl + Type + Cont, data = housing) |
| rr <- regr(formula(m), data = housing) |
| dr1 <- drop1(m) |
| stopifnot(is.data.frame(rr), |
| all.equal(rr[-(3:4)], dr1, check.attributes = FALSE)) |
