| list2env | R Documentation |
From a named list x, create an
environment containing all list components as objects, or
“multi-assign” from x into a pre-existing environment.
list2env(x, envir = NULL, parent = parent.frame(),
hash = (length(x) > 100), size = max(29L, length(x)))
x |
a |
envir |
an |
parent |
(for the case |
hash |
(for the case |
size |
(in the case |
This will be very slow for large inputs unless hashing is used on the environment.
Environments must have uniquely named entries, but named lists need not: where the list has duplicate names it is the last element with the name that is used. Empty names throw an error.
An environment, either newly created (as by
new.env) if the envir argument was NULL,
otherwise the updated environment envir. Since environments
are never duplicated, the argument envir is also changed.
Martin Maechler
environment, new.env,
as.environment; further, assign.
The (semantical) “inverse”: as.list.environment.
L <- list(a = 1, b = 2:4, p = pi, ff = gl(3, 4, labels = LETTERS[1:3]))
e <- list2env(L)
ls(e)
stopifnot(ls(e) == sort(names(L)),
identical(L$b, e$b)) # "$" working for environments as for lists
## consistency, when we do the inverse:
ll <- as.list(e) # -> dispatching to the as.list.environment() method
rbind(names(L), names(ll)) # not in the same order, typically,
# but the same content:
stopifnot(identical(L [sort.list(names(L ))],
ll[sort.list(names(ll))]))
## now add to e -- can be seen as a fast "multi-assign":
list2env(list(abc = LETTERS, note = "just an example",
df = data.frame(x = rnorm(20), y = rbinom(20, 1, prob = 0.2))),
envir = e)
utils::ls.str(e)
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