R workspaces i.e. .R files

Question

How do I start a new .R file default in a new session for new objects in that session?

Answer 1

Workspaces are .RData files, not .R files. .R files are source files, i.e. text files containing code.

It's a bit tricky. If you saved the workspace, then R saves two files in the current working directory : an .RData file with the objects and a .RHistory file with the history of commands. In earlier versions of R, this was saved in the R directory itself. With my version 2.11.1, it uses the desktop.

If you start up your R and it says : "[Previously saved workspace restored]", then it loaded the file ".RData" and ".RHistory" from the default working directory. You find that one by the command

getwd()

If it's not a desktop or so, then you can use

dir()

to see what's inside. For me that doesn't work, as I only have the file "desktop.ini" there (thank you, bloody Windoze).

Now there are 2 options : you manually rename the workspace, or use the command:

save.image(file="filename.RData")

to save the workspaces before you exit. Alternatively, you can set those options in the file Rprofile.site. This is a text file containing the code R has to run at startup. The file resides in the subdirectory /etc of your R directory. You can add to the bottom of the file something like :

fn <- paste("Wspace",Sys.Date(),sep="")
nfiles <- length(grep(paste(fn,".*.RData",sep=""),dir()))
fn <- paste(fn,"_",nfiles+1,".RData",sep="")
options(save.image.defaults=list(file=fn))

Beware: this doesn't do a thing if you save the workspace by clicking "yes" on the message box. You have to use the command

save.image()

right before you close your R-session. If you click "yes", it will still save the workspace as ".RData", so you'll have to rename it again.