Is the input (not) null?

Share:

Description

Checks to see if the input is (not) null.

Usage

1
2
3
4
5
6
7
assert_is_not_null(x, severity = getOption("assertive.severity", "stop"))

assert_is_null(x, severity = getOption("assertive.severity", "stop"))

is_not_null(x, .xname = get_name_in_parent(x))

is_null(x, .xname = get_name_in_parent(x))

Arguments

x

Input to check.

severity

How severe should the consequences of the assertion be? Either "stop", "warning", "message", or "none".

.xname

Not intended to be used directly.

Value

is_null wraps is.null, providing more information on failure. is_not_null returns TRUE in the opposite case. The assert_* functions return nothing but throw an error if the corresponding is_* function returns FALSE.

See Also

is.null.

Examples

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
# Predicate for NULL. Vectors of length zero are not NULL!
is_null(NULL)
is_null(c())
is_null(numeric())

# The opposite check
is_not_null(NULL)
is_not_null(c())
is_not_null(numeric())

# These checks should pass
assert_is_null(NULL)
assert_is_null(c())
assert_is_not_null(NA)