wrapFormula function

Enhance Formula by Wrapping each Term, e.g., by "s(.)"

The main motivation for this function has been the easy construction of a full GAM formula from something as simple as Y ~ ..

The potential use is slightly more general.

wrapFormula(f, data, wrapString = "s(*)")

Arguments

• f: the initial formula; typically something like Y ~ ..
• data: data.frame to which the formula applies; see, formula or also gam or lm.
• wrapString: character string, containing "*", specifying the wrapping expression to use.

Returns

a formula very similar to f; just replacing each additive term by its wrapped version.

Note

There are limits for this to work correctly; notably the right hand side of the formula f should not be nested or otherwise complicated, rather typically just . as in the examples.

Author(s)

Martin Maechler, May 2007.

See Also

formula; gam from package list("mgcv") (or also from package list("gam")).

Examples

myF <- wrapFormula(Fertility ~ . , data = swiss)
myF # Fertility ~ s(Agriculture) + s(....) + ...

if(require("mgcv")) {
   m1 <- gam(myF, data = swiss)
   print( summary(m1) )
   plot(m1, pages = 1) ; title(format(m1$call), line= 2.5)
}

## other wrappers:
wrapFormula(Fertility ~ . , data = swiss, wrap = "lo(*)")
wrapFormula(Fertility ~ . , data = swiss, wrap = "poly(*, 4)")