[R] How to remove all objects except a few specified objects?

[Joshua Wiley]

If you are going to be doing this a lot, you may want to consider
making a little function.  Here is an example 'do not remove'
function.  It defaults to the global environment, but you can always
change it.  Also, if you try to keep a variable name that does not
exist, it will throw an error and not remove anything.  My assumption
is that when one of the names the user typed does not match a current
object, the user made a typo.

dnrm <- function(vars, envir = .GlobalEnv) {
  vars <- c(vars, "dnrm")
  keep <- match(x = vars, table = ls(envir = envir))
  if(any(is.na(keep))) {
    stop(paste("Some of the variables were not found in",
             environmentName(envir)))
  }
  rm(list = ls(envir = envir)[-keep], envir = envir)
  cat("Removed all but", length(keep), "objects from",
      environmentName(envir), fill = TRUE)
}

Cheers,

Josh

On Mon, Aug 23, 2010 at 12:00 PM, Cheng Peng <cpeng at usm.maine.edu> wrote:
>
> How to remove all R objects in the RAM except for a few specified ones?
> rm(list=ls()) removes all R objects in the R work space.
>
> Another question is that whether removing all R objects actually releases
> the RAM? Thanks.
> --
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-- 
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/