^hash._at(index|-index)
^hash._at[first|last]
^hash.at(index|-index)[3.4.4] ^hash.at[first|last][3.4.4] ^hash.at(index|-index)[key|value|hash] [3.4.4] ^hash.at[first|last;key|value|hash] [3.4.4] When adding elements to the hash, each of them gets its own index, starting from zero. The method returns element by the specified index, so ^hash.at(0) is equal to ^hash.at[first].
For negative index it is calculated from the end of the hash, so ^hash.at(-1) is equal to ^hash.at[last].
Optional second argument determines the result:
value - element value will be returned, by default,
key - element key will be returned,
hash - single element hash with be returned.