R: how do you merge/combine two environments?

1) Make one environment the parent of the other and use with(child, ...) :

parent <- new.env(); parent$x <- 1child <- new.env(parent = parent); child$y <- 2with(child, x + y) # x comes from child and y from parent## [1] 3

You can link as many environments as you like in as long a chain as necessary.

Note that if the child were initially created with no parent then you can add a parent later using:

parent.env(child) <- parent

Thus we define LoadData1 and LoadData2 as:

# define LoadData1 to have a parent argumentLoadData1 <- function(parent = emptyenv()) {        # calculation of environment e goes here        parent.env(e) <- parent        e}# define LoadData2 to have a parent argumentLoadData2 <- function(parent = emptyenv()) {        # calculation of environment e goes here        parent.env(e) <- parent        e}# rune1 <- LoadData1()e2 <- LoadData2(parent = e1)with(e2, dataFrom1 + dataFrom2)

If you don't want to modify LoadData1 and LoadData2 from what they are now:

e1 <- LoadData1()e2 <- LoadData2()parent.env(e2) <- e1with(e2, dataFrom1 + dataFrom2)

2) Convert to lists:

with(c(as.list(e1), as.list(e2)), somefunction())

ADDED Second approach.

You can do it by combining them, converting the environments to lists, and then converting back:

E3 <- as.environment(sapply(c(E1,E2),as.list))ls(env=E3)[1] "x" "y"E3$x[1] 25E3$y[1] 7

I made this function:

> appendEnv = function(e1, e2) {+     e1name = deparse(substitute(e1))+     e2name = deparse(substitute(e2))+     listE1 = ls(e1)+     listE2 = ls(e2)+     for(v in listE2) {+         if(v %in% listE1) warning(sprintf("Variable %s is in e1, too!", v))+         e1[[v]] = e2[[v]]+     }+ }> e1 = new.env()> e2 = new.env()> e1$x = 1> e1$y = 2> e2$y = 3> e2$z = 4> appendEnv(e1, e2)Warning message:In appendEnv(e1, e2) : Variable y is in e1, too!> as.list(e1)$x[1] 1$y[1] 3$z[1] 4