FLATTEN
Requires: Write access to configure a questionnaire calculation.
Combines selected lists in stored input order. Input: text and numeric lists. Output: one text list. Text is trimmed and blanks removed; numbers become text.
Example: [' walk ', ''] plus ['rest'] → ['walk', 'rest']. Numeric values become floating-point strings, such as 2.0. An empty selection of data produces an empty list.