How to use a value not in the scope of a function?

Question

How to access variables defined outside the scope of a function.

foo <- "bar"

f <- function(){
  print(foo)
}

I should be able to print "bar"

Answer 1

You can use get():

foo <- "bar"

test <- function(){
  print(get("foo", envir = .GlobalEnv))
}

> test()
[1] "bar"