How to limit the scope of the variables used in a script?

Let's say I've written an R script which uses some va开发者_C百科riables. When I run it, those variables clutter the global R environment. To prevent this, how do I limit the scope of variables used in a script to that script only? Note: I know that one way is to use functions, are there any other ways?

Just use the local=TRUE argument to source and evaluate source somewhere other than your global environment. Here are a few ways to do that (assuming you don't want to be able to access the variables in the script). foo.R just contains print(x <- 1:10).

do.call(source, list(file="c:/foo.R", local=TRUE), envir=new.env())
#  [1]  1  2  3  4  5  6  7  8  9 10
ls()
# character(0)

mysource <- function() source("c:/foo.R", local=TRUE)
mysource()
#  [1]  1  2  3  4  5  6  7  8  9 10
ls()
# [1] "mysource"

sys.source is probably the most straight-forward solution.

sys.source("c:/foo.R", envir=new.env())

You can also evaluate the file in an attached environment, in case you want to access the variables. See the examples in ?sys.source for how to do this.

You can use the local function.