prodlim (version 1.3.7)

readFormula: Read a special formula

Description

Distangle formula with special terms.

Usage

readFormula(formula, specials, specialArgumentNames, alias, unspecified = "unSpec")

Arguments

formula

A formula of the form Hist(time, event) ~ g(a) + f(b) + g(c) where f and g are examples of special functions.

specials

Names of the special functions.

specialArgumentNames

Further arguments of special functions.

alias

List of alias names for special functions

unspecified

Special function for variables that are not specialized.

Value

• A list
• Response
  A lhs-formula, i.e. a character-class formula where the right hand set to ~1
• Intercept
  The Intercept of the formula
• special
  For each special name and the unspecificied name, a list with a character-class formula and specialArguments.
• allVars
  A character-class rhs-formula containing all variables of argument formula

Details

This function restricts the formula syntax to some extend. For example, it is not possible to construct variables inside the formula: This is an error: readFormula(a~b+X(I(c>4)),specials=c("X"))

Instead, one need to construct the variable data$c4 <- data$c>4 and then use

readFormula(a~b+X(c),specials=c("X"))

Examples

readFormula(y~x+f(z),specials=c("f"),unspecified="g")

## suitable construction to serve cmprsk
qFun <- function(x){x^2}
## multiply X1 by time^2 and X2 by time:
readFormula(Hist(time,event)~cov2(X1,tf=qFun)+cov2(X2),
	    specials=c("cov2","cov1"),
	    specialArgumentNames=list("cov2"="tf"),
	    unspecified="cov1")