VGAM (version 1.1-8)

formulavlm: Model Formulae and Term Names for VGLMs

Description

The methods function for formula to extract the formula from a fitted object, as well as a methods function to return the names of the terms in the formula.

Usage

# S3 method for vlm
formula(x, ...)
formulavlm(x, form.number = 1, ...)
term.names(model, ...)
term.namesvlm(model, form.number = 1, ...)

Value

The formula methods function should return something similar to

formula. The term.names methods function should return a character string with the terms in the formula; this includes any intercept (which is denoted by "(Intercept)" as the first element.)

Arguments

x, model

A fitted model object.

form.number

Formula number, is 1 or 2. which correspond to the arguments formula and form2 respectively.

...

Same as formula.

Author

Thomas W. Yee

Details

The formula methods function is based on formula.

See Also

has.interceptvlm.

Examples

# Example: this is based on a glm example
counts <- c(18,17,15,20,10,20,25,13,12)
outcome <- gl(3, 1, 9); treatment <- gl(3, 3)
vglm.D93 <- vglm(counts ~ outcome + treatment, family = poissonff)
formula(vglm.D93)
pdata <- data.frame(counts, outcome, treatment)  # Better style
vglm.D93 <- vglm(counts ~ outcome + treatment, poissonff, data = pdata)
formula(vglm.D93)
term.names(vglm.D93)
responseName(vglm.D93)
has.intercept(vglm.D93)