# Domain Access Functions

Once a domain is specified, domain access functions make it possible for your Analytica expressions to extract information about the domain for a variable.

In complex domain specifications, the domain information may vary along an index (an array-valued domain), in which case the return values from these functions could be array-valued.

## DomainType(X)

Returns the type of domain for variable «X» as one of the following:

- "Automatic"
- "Continuous"
- "Integer"
- "Boolean"
- "Discrete"
- "GroupedInteger"

## DomainLowerBound(X)

For a Continuous or Integer domain types, returns the lower bound (smallest possible value), or -INF when unbounded from below. For a Boolean domain, returns 0. For a GroupedInteger domain returns 1. For other domain types, returns Null.

## DomainUpperBound(X)

For a Continuous or Integer domain types, returns the lower bound (smallest possible value), or INF when unbounded from below. For a Boolean domain, returns 1. For other domain types, returns Null.

## DomainIntegerGroup(X)

For a GroupedInteger domain, returns the textual name of the group. For an unnamed group, returns an empty (zero-length) text string, "". For any other domain type, returns Null.

## DomainAllowed(X)

For a Discrete domain with explicit values, including a *Copy from index* domain, returns a reference to the list of possible values. When the set of possible values varies along one or more indexes, the result will be an array of references.

## DomainNullOk(X)

Returns 1 (true) when a Null value is considered acceptable, i.e., not flagged as out-of-range. Null is often used to indicate missing data. Returns 0 when a Null value is considered out-of-range.

## History

Introduced in Analytica 4.3.

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