delete.response
Modify Terms Objects

### Description

Modifies terms objects to remove a response or variables of the model formula, or creates a formula from character vectors (reformulate).

### Usage

    delete.response(termobj)
    drop.terms(termobj, dropx = NULL, keep.response = FALSE)
    reformulate(termlabels, response = NULL, intercept = TRUE, env = parent.frame())
    ## S3 method for class 'terms':
    x[i]

### Arguments

termobj | an object of class c("terms", "formula").
dropx | a numeric vector. Indicates the position of items in attr(termobj, "term.labels") to drop.
keep.response | a logical value. If TRUE, keeps the response component of termobj. The default is FALSE.
response | a character string. Used as the left-hand side of a model formula.
termlabels | a character vector of a length of at least one. Indicates the right-hand side of a model formula. If termlabels specifies any variables names that include spaces, or are otherwise not parsed by R as names, enclose them with backticks.
intercept | a logical value. If TRUE (the default), the function has an intercept for the formula. If FALSE, add "-1" to the right-hand side of a model formula.
i | subscript expressions used to identify the elements to extract or replace.
env | the environment to attach to the formula that is created by reformulate.

Value

delete.response | returns a "terms" object like termsobj but without response.
drop.terms | returns a "terms" object like termsobj with the designated variables.
reformulate | returns a formula composed of termlabels and response, connected with "~".
"[.terms" | returns a new "terms" object, composed of designated labels and the original response.

See Also
terms.
Examples

    f.fit <- y ~ X1 + X2 + X3
    t.fit <- terms(f.fit)
    delete.response(t.fit)
    drop.terms(t.fit, drop = 1:2, keep.response = FALSE)
    reformulate(c("a", " b", "c"), "y", intercept = FALSE)
    reformulate(c("a", " b", "c"), intercept = TRUE)
    t.fit[1:2]
    t.fit[-2]

Package stats version 6.1.5-18
Package Index