Function: AT_INDEX
Syntax: AT_INDEX(list, index) or list[index]
Description: Returns the list element at the specified index. The index starts at zero and goes up to LENGTH(array) - 1. A negative index can be specified to access elements from the end of the list.`
Sample usage:
AT_INDEX(["a", "b", "c"], 0)returns"a"AT_INDEX(["a", "b", "c"], 1)returns"b"AT_INDEX(["a", "b", "c"], 2)returns"b"AT_INDEX(["a", "b", "c"], 3)returnsnullAT_INDEX(["a", "b", "c"], -1)returns"c"AT_INDEX(["a", "b", "c"], -2)returns"b"