Question

I would like to ask if it is possible to copy/move all the objects of one environment to another, at once. For example:

f1 <- function() {
    print(v1)
    print(v2)
}

f2 <- function() {
    v1 <- 1
    v2 <- 2

    # environment(f1)$v1 <- v1         # It works
    # environment(f1)$v2 <- v2         # It works
    
    environment(f1) <- environment(f2) # It does not work
}

f2()
f1()

Answer 1

There seem to be at least 3 different things you can do:

1. Clone an environment (create an exact duplicate)
2. Copy the content of one environment to another environment
3. Share the same environment

To clone:

# Make the source env
e1 <- new.env()
e1$foo <- 1
e1$.bar <- 2   # a hidden name
ls(e1) # only shows "foo"

# This will clone e1
e2 <- as.environment(as.list(e1, all.names=TRUE))

# Check it...
identical(e1, e2) # FALSE
e2$foo
e2$.bar

To copy the content, you can do what @gsk showed. But again, the all.names flag is useful:

# e1 is source env, e2 is dest env
for(n in ls(e1, all.names=TRUE)) assign(n, get(n, e1), e2)

To share the environment is what @koshke did. This is probably often much more useful. The result is the same as if creating a local function:

f2 <- function() {
  v1 <- 1 
  v2 <- 2

  # This local function has access to v1 and v2
  flocal <- function() {
    print(v1)
    print(v2)
  }

  return(flocal)
} 

f1 <- f2()
f1() # prints 1 and 2