[R] Fwd: Evaluating a function within a pre-defined environment?

[hadley wickham]

On Wed, Dec 9, 2009 at 4:48 PM, David Reiss <dreiss at systemsbiology.org> wrote:
> Ideally I would like to be able to use the function f (in my example)
> as-is, without having to designate the environment as an argument, or
> to otherwise have to use "e$x" in the function body.

e <- new.env()
e$x <- 3
f <- function(xx) x <<- x + xx
environment(f) <- e

f(1)
f(1)
f(2)
e$x

But I think you'd be better off doing it within the usual scoping rules:

new_adder <- function(init = 0) {
  sum <- init
  function(x) {
    sum <<- sum + x
    sum
  }
}

f <- new_adder(3)
f(1)
f(2)

Hadley

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