first_element(x) – Returns the first element in an array
SELECT first_element(array(‘a’,’b’,’c’));
a
SELECT first_element(array());
NULL
Platforms: WhereOS, Spark, Hive
Class: hivemall.tools.array.FirstElementUDF
More functions can be added to WhereOS via Python or R bindings or as Java & Scala UDF (user-defined function), UDAF (user-defined aggregation function) and UDTF (user-defined table generating function) extensions. Custom libraries can be added on via Settings-page or installed from WhereOS Store.