On 02/12/2017 5:48 AM, Alexander Shenkin wrote:
Hi all,
I often keep code in separate files for organizational purposes, and
source() that code from higher level scripts. One problem is that those
sourced files often create temporary variables that I don't want to keep
around. I could clean up after myself with lots of rm()'s, but that's a
pain, and is messy.
I'm wondering if one solution might be to source the code in a temporary
environment, assign outputs of interest to the .GlobalEnv with <<-, and
then delete the environment afterwards. One way to do this:
file.r:
temp1 = 1
temp2 = 2
desired_var <<- temp1 + temp2
console:
temp_e = new.env()
source("file.r", local = temp_e)
rm(temp_e)
It's a bit messy to create and delete environments, so I tried what
others have referred to:
source("file.r", local = attach(NULL))
This, however, results in a persistent "NULL" environment in the search
path.
> search()
".GlobalEnv" "package:bindrcpp" "NULL"
"tools:rstudio" "package:stats" "package:graphics"
"package:grDevices" "package:utils" "package:datasets"
"package:methods" "Autoloads" "package:base"
Of course, functions are built to encapsulate like this (and do so in
their own temporary environment), but in many cases, turning the sourced
code into functions is possible but clunky.
Any thoughts or suggestions would be much appreciated.
I would wrap the calls in the local() function, or put them in a
function and call that. That is,
local({
source("file.R", local = TRUE)
})
or
sourceit <- function() {
source("file.R", local = TRUE)
}
sourceit()
With respect to your last comment (turning the code in file.R into
functions which don't leave their locals behind): I think that would be
the best solution. You may find it clunky now, but in the long run it
likely will help you to make better code.
Duncan Murdoch
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