Function

length( array )

This function returns the number of elements in an array.

See also:

• isnull(): Use this function to determine if the process variable or array contains null values.
• count(): Use this function to include null elements in the number of elements in a process variable or array.

Parameters

Returns

Integer

Usage considerations

Null elements

In most cases, this function does not count null elements. length({null, 2}) returns 1 because the null is not counted.

There are scenarios though where null values will be counted as part of a list. For example, let's say you have a local variable called local!result, which stores the results of a query. If the query returns a null value, then the expression length({local!result, 2}) may return 2. When local!result is a List of Text String with a single null field, Appian evaluates the expression as length({{null}, 2}) and returns 2.

If this function is used on a null result from the Query Database smart service, the expression may fail to evaluate and cause an error. To avoid an error, first check the result set for a null value using the isnull() function before attempting to count the result set using the length() function.

Examples

Length of list

1
length({10, 20, 30})

Returns 3.

Length of list with null values

1
length({10, null, 30})

Returns 2. Null values are skipped.

Length of list with nested list

1
length({1, 2, merge({1}, {2})})

Returns 3. Nested lists are counted as one value.

Length of list with nested null list

1
length({1, 2, merge({null})})

Returns 3. Nested lists with only null values are counted as one value.

Feature compatibility