View source for Domain Access Functions


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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 [[reference]]s.  

== 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]].

==See Also==
* [[Data Type Functions]]