efficiently move environment from inside function to global environment

Question

I have a function that creates an environment within it and i wish to assign that environment to the global environment. At present i do this by assigning the environment to globalenv() as the final step -- as follows:

funfun <- function(inc = 1){
    dataEnv <- new.env()
    dataEnv$d1 <- 1 + inc
    dataEnv$d2 <- 2 + inc
    dataEnv$d3 <- 2 + inc
    assign('dataEnv', dataEnv, envir = globalenv())
}

It feels like i should be able to do something to make dataEnv persisit when the function funfun ends (to save copying the environment at the end) however my attempts, such as dataEnv <- new.env(parent = globalenv()), have not worked.

Why does it fail? Is this possible?

Also, what is the most efficient way of doing this?

My tables are very large at times, and the copying will become an issue as the project grows.

Answer 1

Your environment is not being destroyed when you exit the function. You just need to return a reference to it.

funfun <- function(inc = 1){
  dataEnv <- new.env(parent=globalenv())
  dataEnv$d1 <- 1 + inc
  dataEnv$d2 <- 2 + inc
  dataEnv$d3 <- rnorm(10000)
  return(dataEnv)
}


myEnv <- funfun()
object.size(myEnv)

Get some stuff out

head(myEnv$d3)