Disable graph display in R

Question

I am trying to disable the graph display in R.

I am reading Disable GUI, graphics devices in R , but the only solution is to write the graph to a file.

What if I do not want to pollute the workspace, and what if I do not have write permission? I tried options(device=NULL) but that didn't work.

The context is the NbClust package: I want NbClust() return, but I do not want to display the graph it makes.

Thanks in advance!

edit: Here is a reproducible example using data from a rattle package :)

 data(wine, package="rattle") df <- scale (wine[-1]) library(NbClust) # This produces a graph output which I don't want nc <- NbClust(df, min.nc=2, max.nc=15, method="kmeans") # This is the plot I want ;) barplot(table(nc$Best.n[1,]), xlab="Numer of Clusters", ylab="Number of Criteria", main="Number of Clusters Chosen by 26 Criteria") 

Answer 1

You can wrap the call in

 pdf(file = NULL) 

and

 dev.off() 

This sends all the output to a null file, which effectively hides it.

Answer 2

Fortunately, it seems that NbClust is one gigantic messy function with some other functions in it and lots of bad code. Bookmarking is done in one of two places.

Create a copy of NbClust :

 > MyNbClust = NbClust 

and then edit this function. Change the title to:

 MyNbClust <- function (data, diss = "NULL", distance = "euclidean", min.nc = 2, max.nc = 15, method = "ward", index = "all", alphaBeale = 0.1, plotetc=FALSE) { 

and then wrap the build code in if blocks. On line 1588:

  if(plotetc){ par(mfrow = c(1, 2)) [etc] cat(paste(... } 

and similarly around line 1610. Save. Now use:

  nc = MyNbClust(...etc....) 

and you don’t see any graphs unless you add plotetc=TRUE .

Then ask the developers to enable your patch.