Assign multiple objects to .GlobalEnv from within a function

Update of 2018-10-10:

The most succinct way to carry out this specific task is to use list2env() like so:

## Create an example list of five data.framesdf <- data.frame(x = rnorm(25),                 g = rep(factor(LETTERS[1:5]), 5))LIST <- split(df, df$g)## Assign them to the global environmentlist2env(LIST, envir = .GlobalEnv)## Check that it workedls()## [1] "A"    "B"    "C"    "D"    "df"   "E"    "LIST"

Original answer, demonstrating use of assign()

You're right that assign() is the right tool for the job. Its envir argument gives you precise control over where assignment takes place -- control that is not available with either <- or <<-.

So, for example, to assign the value of X to an object named NAME in the the global environment, you would do:

assign("NAME", X, envir = .GlobalEnv)

In your case:

df <- data.frame(x = rnorm(25),                 g = rep(factor(LETTERS[1:5]), 5))LIST <- split(df, df$g)NAMES <- c("V", "W", "X", "Y", "Z")lapply(seq_along(LIST),        function(x) {           assign(NAMES[x], LIST[[x]], envir=.GlobalEnv)        })ls()[1] "df"    "LIST"  "NAMES" "V"     "W"     "X"     "Y"     "Z"    

If you have a list of object names and file paths you can also use mapply:

object_names <- c("df_1", "df_2", "df_3")file_paths   <- list.files({path}, pattern = ".csv", full.names = T)    mapply(function(df_name, file)            assign(df_name, read.csv(file), envir=.GlobalEnv),       object_names,       file_paths)

• I used list.files() to construct a vector of all the .csv files in aspecific directory. But file_paths could be written or constructed in any way.
• If the files you want to read in are in the current workingdirectory, then file_paths could be replaced with a character vector offile names.
• In the code above, you need to replace {path} with astring of the desired directory's path.