formulavlm {VGAM} | R Documentation

## 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 class 'vlm'
    formula(x, ...)
    formulavlm(x, form.number = 1, ...)
    term.names(model, ...)
    term.namesvlm(model, form.number = 1, ...)

### 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`.

### Details

The `formula` methods function is based on `formula`.

### 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.)

### Author(s)

Thomas W. Yee

### 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)

[Package VGAM version 1.1-1 Index]