env_get()
extracts an object from an enviroment env
. By
default, it does not look in the parent environments.
env_get_list()
extracts multiple objects from an environment into
a named list.
env_get(env = caller_env(), nm, default, inherit = FALSE, last = empty_env())
env_get_list(
env = caller_env(),
nms,
default,
inherit = FALSE,
last = empty_env()
)
An environment.
Names of bindings. nm
must be a single string.
A default value in case there is no binding for nm
in env
.
Whether to look for bindings in the parent environments.
Last environment inspected when inherit
is TRUE
.
Can be useful in conjunction with base::topenv()
.
An object if it exists. Otherwise, throws an error.
env_cache()
for a variant of env_get()
designed to
cache a value in an environment.
parent <- child_env(NULL, foo = "foo")
env <- child_env(parent, bar = "bar")
# This throws an error because `foo` is not directly defined in env:
# env_get(env, "foo")
# However `foo` can be fetched in the parent environment:
env_get(env, "foo", inherit = TRUE)
#> [1] "foo"
# You can also avoid an error by supplying a default value:
env_get(env, "foo", default = "FOO")
#> [1] "FOO"