index() Function

Function

index( data, index, default )

Returns the data[index] if it is valid or else returns the default value.

See also: property(): This function acts as an alias to the index() function especially when applied over custom data types.

Parameters

Keyword	Type	Description
data	Any Type	A homogeneous array, whose indexed value is expected. Can also be a dictionary, map, CDT, or Record.
index	Any Type	The index or array of indices of the data. Index can be an integer, text, or a record type field reference.
default	Any Type	The default value to be returned if the data or the index is invalid, e.g. if the data itself is empty or the index is not found in the data. The type of the default value must be the same as that of the elements of the data. This parameter is optional.

Returns

Any Type

Usage considerations

The type of the default value must be same as that of the elements in the array.

When the data is a dictionary, if the index is not found in the dictionary, the default will be ignored and a null value will be returned. Consider using a map instead of a dictionary.

Examples

Retrieving a value at a single index

index({10, 20, 30}, 2, 1) returns 20

Return the value of a field name within a CDT where the array is the PV and the index is the field name

index(pv!person, "firstName", "") returns the value of the "firstName" field in a CDT of person with two fields (firstName and lastName)

Retrieving values at multiple indices

index({10, 20, 30}, {1, 3}, 0) returns 10, 30

Retrieving values at repeated indices

index({10, 20, 30}, {1, 1, 3}, 0) returns 10, 10, 30

Retrieving the value of a CDT field using the field name as the index argument

index(topaginginfo(1, 10), "startIndex", 0) returns 1

Retrieving the value of a map field using the field name as the index argument

index(a!map(a: 1, b: 2), "b", 0) returns 2

Retrieving the value of a record using the record field reference as the index argument

index(recordType!Department(name: "Engineering"), recordType!Department.fields.name, "") returns "Engineering"

Feature compatibility

The table below lists this function's compatibility with various features in Appian.

Feature	Compatibility	Note
Portals	Compatible
Offline Mobile	Compatible
Sync-Time Custom Record Fields	Compatible	Can be used to create a custom record field that only evaluates at sync time.
Real-Time Custom Record Fields	Incompatible
Process Reports	Compatible
Process Events	Compatible

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