Are all elements in a list null or data.frames?

Checks two things: that `x` is a list, and that all elements in `x` are `NULL` or data.frames.

Usage

is_all_list_elements_null_or_df(x)

Arguments

x

An object

Value

TRUE or FALSE.

See also

vignette("csutil", package = "csutil"), which runs all four predicates on small example lists.

Other list predicates: is_all_list_elements_null_or_fully_named_list(), is_all_list_elements_null_or_list(), is_fully_named_list()

Examples

is_all_list_elements_null_or_df(data.frame())
#> [1] FALSE
is_all_list_elements_null_or_df(list(data.frame()))
#> [1] TRUE
is_all_list_elements_null_or_df(list(1, NULL))
#> [1] FALSE
is_all_list_elements_null_or_df(list(data.frame(), NULL))
#> [1] TRUE
is_all_list_elements_null_or_df(list("a"=1, 2))
#> [1] FALSE