#### 7.7.5 Set-Membership Functions

Set membership functions determine whether a value is a member of a set.
They take a set of numeric arguments or a set of string arguments, and
produce Boolean results.

String comparisons are performed according to the rules given in
Relational Operators. User-missing string values are treated as
valid values.

- Function:
**ANY** `(``value`, `set` [, `set`]…)

¶
Returns true if `value` is equal to any of the `set` values,
and false otherwise. For numeric arguments, returns system-missing if
`value` is system-missing or if all the values in `set` are
system-missing. If `value`

- Function:
**RANGE** `(``value`, `low`, `high` [, `low`, `high`]…)

¶
Returns true if `value` is in any of the intervals bounded by
`low` and `high` inclusive, and false otherwise. `low`
and `high` must be given in pairs. Returns system-missing if any
`high` is less than its `low` or, for numeric arguments, if
`value` is system-missing or if all the `low`-`high` pairs
contain one (or two) system-missing values. A pair does not match
`value` if either `low` or `high` is missing, even if
`value` equals the non-missing endpoint.