A numeric or short string variable may have a set of user-missing
values (see MISSING VALUES), represented
struct missing_values (see User-Missing Values).
The most frequent operation on a variable's missing values is to query whether a value is user- or system-missing:
Tests whether value is a missing value of the given class for variable var and returns true if so, false otherwise.
var_is_num_missingmay only be applied to numeric variables;
var_is_str_missingmay only be applied to string variables. For string variables, value must contain exactly as many characters as var's width.
)is equivalent to
_missing (var_get_missing_values (var
In addition, a few functions are provided to work more directly with a
struct missing_valuesassociated with var. The caller must not modify the returned structure. The return value is always non-null.
Changes var's missing values to a copy of miss, or if miss is a null pointer, clears var's missing values. If miss is non-null, it must have the same width as var or be resizable to var's width (see mv_resize). The caller retains ownership of miss.
Clears var's missing values. Equivalent to