[R] Tip: Working directory in titlebar

[Michael Prager]

I hope others may find this useful.  I use R in many different 
directories.  By adding the following line to the .Rprofile file:

utils:::setWindowTitle(paste("-",getwd()))

the titlebar of each R instance shows the directory from which it was 
started. I have tested this with rterm.exe and rgui.exe under Windows 
and with RECENT versions of R only.

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For changing directories during a session, I use the following function, 
a slight modification of Andy Liaw's cd() function that also changes the 
titlebar:

cd <- function(dir = tclvalue(tkchooseDirectory()), saveOld=NA, 
loadNew=TRUE) {
    # From Andy Liaw  ... additions by MHP
    # Change the working directory during an R session
    #
    # First check that the tcl-tk package is available:
    stopifnot(require(tcltk))
    # Print any error message from trying to load:
    if (.Platform$OS.type=="windows") flush.console()  ## MHP
    # Warn user if saving existing workspace was not chosen: (MHP)
    if (is.na(saveOld)) {
      tmp = tclvalue(tkmessageBox(message="Save current workspace image?",
         type="yesnocancel",title="Changing directories",icon="question"))
         saveOld = switch(tmp, "yes"=TRUE, "no"=FALSE, 
"cancel"=return(invisible(NULL)))
         }
    # Save old workspace:
    if (saveOld) save.image(compress=TRUE)
    # Change directory:
    # Note: the need to evaluate "dir" on the next line causes the 
"tclvalue" call
    #    in the function definition (first line) to take place now:
    if (dir=="") return(invisible(NULL))  # Fail gracefully if "CANCEL" 
chosen from TK dialog (MHP)
    setwd(dir)
    # Remove all the data from the old working directory:
    rm(list=ls(all=TRUE, envir=.GlobalEnv), envir=.GlobalEnv)
    # Change the window title:
    setWindowTitle(paste("-",dir))
    # Load the new data:
    if (loadNew) {
         if (file.exists(".RData")) {
            loaded <- load(".RData", envir=.GlobalEnv)
            return(invisible(loaded))
         }
         else {
            cat("Warning: .RData not found in new directory\n")
            return(invisible(FALSE))
         }
    }
}

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Although both these bits of code have been used, they may have errors.  
Comments and corrections welcome.

-- 
Michael H. Prager, Ph.D.
Population Dynamics Team
NOAA Center for Coastal Habitat and Fisheries Research
NMFS Southeast Fisheries Science Center
Beaufort, North Carolina  28516  USA
http://shrimp.ccfhrb.noaa.gov/~mprager/