FLATTEN

Description

FLATTEN takes a list of dictionaries and extracts values from them. Given a list of dictionaries and a key (or a tuple of keys), it returns a flat list of the values at that key across all dictionaries.

If called with no second argument, it concatenates the elements of the list into a single value.

Example with a single key

FLATTEN([{"key": "a", "name": "Alice"}, {"key": "b", "name": "Bob"}], "key")

This extracts the value at "key" from each dictionary, returning ["a", "b"].

Example with multiple keys

FLATTEN([{"key": "a", "age": 25, "name": "Alice"}, {"key": "b", "age": 30, "name": "Bob"}], ("key", "name"))

This returns only the specified keys from each dictionary: [{"key": "a", "name": "Alice"}, {"key": "b", "name": "Bob"}].

Example without a key

FLATTEN([["a", "b"], ["c", "d"]])

This concatenates the sublists into a single list, returning ["a", "b", "c", "d"].