Override a function that is imported in a namespace

Question

As the termplot function in R is containing some weird code that is giving me annoying bugs, I want to override it in my own test code until I find a more perma

Answer 1

Try overwriting the function that you are calling termplot from. At a guess, this is plot.gam in the mgcv package.

First load the necessary package.

library(mgcv)

Here's your alternate termplot function, added to the stats namespace.

my.termplot <- function (model, ...) 
{
  message("In my.termplot")
}

unlockBinding("termplot", as.environment("package:stats"))
assign("termplot", my.termplot, as.environment("package:stats"))
lockBinding("termplot", as.environment("package:stats"))

Likewise, here's the wrapper function, added to the mgcv namespace.

my.plot.gam <- function (x, ...) 
{
  message("In my.plot.gam")
  my.termplot()
}

unlockBinding("plot.gam", as.environment("package:mgcv"))
assign("plot.gam", my.plot.gam, as.environment("package:mgcv"))
lockBinding("plot.gam", as.environment("package:mgcv"))

Here's an example to test it, taken from ?gam.

dat <- gamSim(1, n = 400, dist = "normal", scale = 2)
b <- gam(y ~ s(x0) + s(x1) + s(x2) + s(x3), data = dat)
plot(b)