FunctionArrayNextPrevious

Library "FunctionArrayNextPrevious"
Methods to iterate through a array by a fixed anchor point.

array_next(array, start_index) retrieves the next value of the internal pointer index.
  Parameters:
    array: (any array type), array to iterate.
    start_index: int, anchor index to start indexing.

array_previous(array, start_index) retrieves the previous value of the internal pointer index.
  Parameters:
    array: (any array type), array to iterate.
    start_index: int, anchor index to start indexing.

note: regrettably is not possible to have global reference index without juggling it in the parameters and tracking it externally to switch between next/previous